x86/mm, efi: Use early_ioremap() in arch/x86/platform/efi/efi-bgrt.c

Use early_ioremap() to map an I/O-area instead of
early_memremap().

Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: matt.fleming@intel.com
Link: http://lkml.kernel.org/r/1424769211-11378-5-git-send-email-jgross@suse.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>