efi_loader: use byteshift unaligned access helper

efi_loader: use byteshift unaligned access helper

Calling unaligned/access-ok.h version of put_unaligned_le64()
causes data abort in arm 32-bit QEMU.

The similar issue also occurs in linux kernel,
unaligned/access-ok.h is no longer used in linux kernel[1].

This commit uses the unaligned/be_byteshift.h and
unaligned/le_byteshift.h helper instead of unaligned/access-ok.h.

[1]https://lore.kernel.org/all/20210507220813.365382-8-arnd@kernel.org/

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>