drm/amdgpu: set cp fw address set for gfx v12

Split PFF/ME/MEC firmware address setting function
from related load microcode funtion, as it's also
needed for rlc autolad.

Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>