drm/radeon: make missing smc ucode non-fatal

The smc ucode is required for dpm (dynamic power
management), but if it's missing just skip dpm setup
and don't disable acceleration.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=67876

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index 6a7a80b..c557850 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -1176,9 +1176,13 @@
 	case CHIP_VERDE:
 	case CHIP_OLAND:
 	case CHIP_HAINAN:
-		/* DPM requires the RLC */
+		/* DPM requires the RLC, RV770+ dGPU requires SMC */
 		if (!rdev->rlc_fw)
 			rdev->pm.pm_method = PM_METHOD_PROFILE;
+		else if ((rdev->family >= CHIP_RV770) &&
+			 (!(rdev->flags & RADEON_IS_IGP)) &&
+			 (!rdev->smc_fw))
+			rdev->pm.pm_method = PM_METHOD_PROFILE;
 		else if (radeon_dpm == 1)
 			rdev->pm.pm_method = PM_METHOD_DPM;
 		else