x86/e820: Add a new e820 table update helper

Add a new API helper e820__range_update_table() with which to update an
arbitrary e820 table. Move all current users of
e820__range_update_kexec() to this new helper.

  [ bp: Massage. ]

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/b726af213ad55053f8a7a1e793b01bb3f1ca9dd5.1714090302.git.ashish.kalra@amd.com