drm/amdgpu/pm: Use inline function for IP version check

Use existing inline function for IP version check.

Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org