arm64: Support 6 arguments for SMC

According to the ARM SMC Calling Convention (ARM DEN 0028A):
SMC64: A 64-bit interface which can be used only by 64-bit
client code and which passes up to six 64-bit arguments.
And arguments are passed in registers X0-X6.

BUG=b:249552664
TEST=Test with the cros_widevine SMC
BRANCH=None

Change-Id: If87c22052065736f195bd6af1a430dd6d6aef01e
Signed-off-by: Yi Chou <yich@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/depthcharge/+/4333402
Reviewed-by: Julius Werner <jwerner@chromium.org>
3 files changed