drm/i915: Quiet the message on get/setparam ioctl with an unknown value.

Getting an unknown get/setparam used to be more significant back when they
didn't change much.  However, now that we're in the git world we're using
them instead of a monotonic version number to signal feature availability,
so clients ask about unknown params on older kernels more often.
Signed-off-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDave Airlie <airlied@linux.ie>

drivers/gpu/drm/i915/i915_dma.c

@@ -735,7 +735,7 @@ static int i915_getparam(struct drm_device *dev, void *data,
 		value = dev_priv->num_fence_regs - dev_priv->fence_reg_start;
 		break;
 	default:
-		DRM_ERROR("Unknown parameter %d\n", param->param);
+		DRM_DEBUG("Unknown parameter %d\n", param->param);
 		return -EINVAL;
 	}
 
@@ -775,7 +775,7 @@ static int i915_setparam(struct drm_device *dev, void *data,
 		dev_priv->fence_reg_start = param->value;
 		break;
 	default:
-		DRM_ERROR("unknown parameter %d\n", param->param);
+		DRM_DEBUG("unknown parameter %d\n", param->param);
 		return -EINVAL;
 	}