UPSTREAM: arm64/efi: set EFI_ALLOC_ALIGN to 64 KB

Set EFI_ALLOC_ALIGN to 64 KB so that all allocations done by the stub
are naturally compatible with a 64 KB granule kernel.

Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

(cherry picked from commit 1bd0abb0c924a8b28c6466cdd6bb34ea053541dc)
Signed-off-by: Tomasz Figa <tfiga@chromium.org>

Bug: 24475017

Change-Id: I3de82baa1ed24b38152dc9c1402816fc61e5157c
Signed-off-by: Kees Cook <keescook@google.com>