This patch adds interface to check fw version for smu.
It's to send msg GetDriverIfVersion to check if the return value is equal with
DRIVER_IF_VERSION of smc header.

v2: add detailed info to describe this function
Signed-off-by: Huang Rui <ray.huang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>