Merge remote-tracking branch 'efi/urgent' into x86/urgent

There have been reports of EFI crashes since -rc1. The following two
commits fix known issues.

 * Fix boot failure on 32-bit EFI due to the recent EFI memmap changes
   merged during the merge window - Borislav Petkov

 * Avoid a crash during efi_bgrt_init() by detecting invalid BGRT
   headers based on the 'status' field.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>