configure: remove bogus linux-user check

linux-user=yes is not a reliable identifier that linux-user targets
have been selected. user targets can be selected via --target-list
as well.

configure

@@ -1249,7 +1249,6 @@ fi
 # have syscall stubs for these implemented.
 #
 atfile=no
-if [ "$linux_user" = "yes" ] ; then
 cat > $TMPC << EOF
 #define _ATFILE_SOURCE
 #include <sys/types.h>
@@ -1266,7 +1265,6 @@ EOF
 if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null > /dev/null ; then
   atfile=yes
 fi
-fi
 
 # Check for inotify functions when we are building linux-user
 # emulator.  This is done because older glibc versions don't
@@ -1274,7 +1272,6 @@ fi
 # don't provide them even if kernel supports them.
 #
 inotify=no
-if [ "$linux_user" = "yes" ] ; then
 cat > $TMPC << EOF
 #include <sys/inotify.h>
 
@@ -1288,7 +1285,6 @@ EOF
 if $cc $ARCH_CFLAGS -o $TMPE $TMPC 2> /dev/null > /dev/null ; then
   inotify=yes
 fi
-fi
 
 # check if utimensat and futimens are supported
 utimens=no