ATA6r1 and ATA6r3, which caused drives conform to ATA6r3 or later to
reject LBA28 commands at sector 0xfffffff.
Get the right idea from the LBA48 boundary from IDENTIFY words 60-61.
Remove the WD_QUIRK_FORCE_LBA48 quirk, associated tables entries and
autodetect code, it's not needed any more.
Based on patch sent to teck-kern by Christoph Badura, use of words 60-61
instead of a constant for the LBA48 boundary by me.
fc6ebcbc61