drm/amdgpu: load ta firmware for sienna cichlid

call psp_int_ta_microcode() to parse the ta firmware.

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: John Clements <John.Clements@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>