drm/amdgpu: skip VEGAM MC firmware load

Directly loaded by VBIOS
Signed-off-by: Leo Liu <leo.liu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c

@@ -231,6 +231,7 @@ static int gmc_v8_0_init_microcode(struct amdgpu_device *adev)
 	case CHIP_FIJI:
 	case CHIP_CARRIZO:
 	case CHIP_STONEY:
+	case CHIP_VEGAM:
 		return 0;
 	default: BUG();
 	}