drm/msm: Demote debug message

Mesa attempts to allocate a cached-coherent buffer in order to determine
if cached-coherent is supported.  Resulting in seeing this error message
once per process with newer mesa.  But no reason for this to be more
than a debug msg.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20211111230214.765476-1-robdclark@gmail.comSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem.c

@@ -1120,7 +1120,7 @@ static int msm_gem_new_impl(struct drm_device *dev,
 			break;
 		fallthrough;
 	default:
-		DRM_DEV_ERROR(dev->dev, "invalid cache flag: %x\n",
+		DRM_DEV_DEBUG(dev->dev, "invalid cache flag: %x\n",
 				(flags & MSM_BO_CACHE_MASK));
 		return -EINVAL;
 	}