efi_loader: Assure fitImage from capsule is used from 8-byte aligned address

efi_loader: Assure fitImage from capsule is used from 8-byte aligned address

The fitImage may be stored in EFI update capsule at address that
is not aligned to 8 bytes. Since fitImage is a DT, new version of
libfdt 1.7.2 rejects such an unaligned DT. Patch the code and copy
the fitImage into aligned buffer in case it is not aligned. This
does increase overhead for unaligned fitImages in EFI capsules, but
tries to keep the overhead low for aligned ones.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>