Revert "x86/kexec: Allocate PGD for x86_64 transition page tables separately"

This reverts commit 6821918f which is
commit 4b5bc2ec upstream.

The patch it relies on is not in the 6.1.y tree, and has been reported
to cause problems, so let's revert it for now.

Reported-by: Eric Hagberg <ehagberg@janestreet.com>
Link: https://lore.kernel.org/r/CAAH4uRBxJ_XvYjCpgYXHqrKSNj6x9pA7X6NBPNTekeQ90DQSJA@mail.gmail.com


Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>