Add a generic GRUB_PE32_MAGIC definition for the PE 'MZ' tag and delete
the existing one in arm64/linux.h.
Update arm64 Linux loader to use this new definition.
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
There is nothing ARM64 (or even ARM) specific about the efi fdt helper
library, which is used for locating or overriding a firmware-provided
devicetree in a UEFI system - so move it to loader/efi for reuse.
Move the fdtload.h include file to grub/efi and update path to
efi/fdtload.h in source code referring to it.
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>