There is no bfd "arm64". The correct bfdname is "aarch64". Fix it. With
this change libpayload will build with the AArch64 GCC.
Change-Id: If7a6b14691107c5d4fc67c3cd3990ecc849d4af1
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43125
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
492d55fa46