Split of the remapping code from efi_config_init() so that the caller
can perform its own remapping. This is necessary to correctly handle
virtually remapped UEFI memory regions under kexec, as efi.systab will
have been updated to a virtual address.
Acked-by: NMatt Fleming <matt.fleming@intel.com>
Tested-by: NLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>