The EFI page definitions and macros are generic and should not be confined
to arm64 headers - so move to efi/memory.h.
Also add EFI_PAGE_SIZE macro.
Update loader sources to reflect new header location.
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>