drm/amdgpu: modify GCR_GENERAL_CNTL for Vangogh

GCR_GENERAL_CNTL is defined differently in gc_10_1_0_offset.h and
gc_10_3_0_offset.h. Update GCR_GENERAL_CNTL for Vangogh.

Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>