Add UPDATING note about radeon firmware image mistake.

UPDATING

@@ -1,4 +1,4 @@
-$NetBSD: UPDATING,v 1.301 2019/07/27 07:55:18 martin Exp $
+$NetBSD: UPDATING,v 1.302 2019/09/03 15:38:52 riastradh Exp $
 
 This file (UPDATING) is intended to be a brief reference to recent
 changes that might cause problems in the build process, and a guide for
@@ -19,6 +19,87 @@ See also: BUILDING, build.sh, Makefile.
 Recent changes:
 ^^^^^^^^^^^^^^^
 
+20190903:
+
+	File with names that coincide with existing files' names on
+	case-insensitive file systems were inadvertently committed, for
+	radeon GPU firmware.  We cannot mark these as obsolete for
+	postinstall to fix, so if you updated src since 2019-08-26, and
+	ran build.sh distribution or ran build.sh release, you must
+	manually delete the following files in your DESTDIR (which is
+	usually $OBJDIR/destir.$ARCH), or from / if you have installed
+	them:
+
+		/libdata/firmware/radeon/bonaire_ce.bin
+		/libdata/firmware/radeon/bonaire_mc.bin
+		/libdata/firmware/radeon/bonaire_me.bin
+		/libdata/firmware/radeon/bonaire_mec.bin
+		/libdata/firmware/radeon/bonaire_pfp.bin
+		/libdata/firmware/radeon/bonaire_rlc.bin
+		/libdata/firmware/radeon/bonaire_sdma.bin
+		/libdata/firmware/radeon/bonaire_smc.bin
+		/libdata/firmware/radeon/bonaire_uvd.bin
+		/libdata/firmware/radeon/hainan_ce.bin
+		/libdata/firmware/radeon/hainan_mc.bin
+		/libdata/firmware/radeon/hainan_me.bin
+		/libdata/firmware/radeon/hainan_pfp.bin
+		/libdata/firmware/radeon/hainan_rlc.bin
+		/libdata/firmware/radeon/hainan_smc.bin
+		/libdata/firmware/radeon/hawaii_ce.bin
+		/libdata/firmware/radeon/hawaii_mc.bin
+		/libdata/firmware/radeon/hawaii_me.bin
+		/libdata/firmware/radeon/hawaii_mec.bin
+		/libdata/firmware/radeon/hawaii_pfp.bin
+		/libdata/firmware/radeon/hawaii_rlc.bin
+		/libdata/firmware/radeon/hawaii_sdma.bin
+		/libdata/firmware/radeon/hawaii_smc.bin
+		/libdata/firmware/radeon/kabini_ce.bin
+		/libdata/firmware/radeon/kabini_me.bin
+		/libdata/firmware/radeon/kabini_mec.bin
+		/libdata/firmware/radeon/kabini_pfp.bin
+		/libdata/firmware/radeon/kabini_rlc.bin
+		/libdata/firmware/radeon/kabini_sdma.bin
+		/libdata/firmware/radeon/kaveri_ce.bin
+		/libdata/firmware/radeon/kaveri_me.bin
+		/libdata/firmware/radeon/kaveri_mec.bin
+		/libdata/firmware/radeon/kaveri_mec2.bin
+		/libdata/firmware/radeon/kaveri_pfp.bin
+		/libdata/firmware/radeon/kaveri_rlc.bin
+		/libdata/firmware/radeon/kaveri_sdma.bin
+		/libdata/firmware/radeon/mullins_ce.bin
+		/libdata/firmware/radeon/mullins_me.bin
+		/libdata/firmware/radeon/mullins_mec.bin
+		/libdata/firmware/radeon/mullins_pfp.bin
+		/libdata/firmware/radeon/mullins_rlc.bin
+		/libdata/firmware/radeon/mullins_sdma.bin
+		/libdata/firmware/radeon/oland_ce.bin
+		/libdata/firmware/radeon/oland_mc.bin
+		/libdata/firmware/radeon/oland_me.bin
+		/libdata/firmware/radeon/oland_pfp.bin
+		/libdata/firmware/radeon/oland_rlc.bin
+		/libdata/firmware/radeon/oland_smc.bin
+		/libdata/firmware/radeon/pitcairn_ce.bin
+		/libdata/firmware/radeon/pitcairn_mc.bin
+		/libdata/firmware/radeon/pitcairn_me.bin
+		/libdata/firmware/radeon/pitcairn_pfp.bin
+		/libdata/firmware/radeon/pitcairn_rlc.bin
+		/libdata/firmware/radeon/pitcairn_smc.bin
+		/libdata/firmware/radeon/tahiti_ce.bin
+		/libdata/firmware/radeon/tahiti_mc.bin
+		/libdata/firmware/radeon/tahiti_me.bin
+		/libdata/firmware/radeon/tahiti_pfp.bin
+		/libdata/firmware/radeon/tahiti_rlc.bin
+		/libdata/firmware/radeon/tahiti_smc.bin
+		/libdata/firmware/radeon/verde_ce.bin
+		/libdata/firmware/radeon/verde_mc.bin
+		/libdata/firmware/radeon/verde_me.bin
+		/libdata/firmware/radeon/verde_pfp.bin
+		/libdata/firmware/radeon/verde_rlc.bin
+		/libdata/firmware/radeon/verde_smc.bin
+
+	We will re-import these radeon firmware images another way
+	later.
+
 20190727:
 	The uefi bootloader has gained tftp support and needs a clean
 	build. If you do update builds, manually clean its object