x86, bios: By default, reserve the low 64K for all BIOSes

The laundry list of BIOSes that need the low 64K reserved is getting
very long, so make it the default across all BIOSes.  This also allows
the code to be simplified and unified with the reservation code for
the first 4K.

This resolves kernel bugzilla 16661 and who knows what else...

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <tip-*@git.kernel.org>