Revert "x86, mm: Include the entire kernel memory map in trampoline_pgd"

Revert "x86, mm: Include the entire kernel memory map in trampoline_pgd"

This reverts commit 6e216f447bce0c9588f26e3b6f3f358f43524840.

It causes odd bootup problems on x86-64.  Markus Trippelsdorf gets a
repeatable oops, and I see a non-repeatable oops (or constant stream of
messages that scroll off too quickly to read) that seems to go away with
this commit reverted.

So we don't know exactly what is wrong with the commit, but it's
definitely problematic, and worth reverting sooner rather than later.

Bisected-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: H Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>