drm/radeon: radeon_enable_vblank should return negative error

radeon_enable_vblank <- drm_vblank_get <- drm_wait_vblank and drm_wait_vblank returns negative values on error

---
compile tested only

---
 drivers/char/drm/radeon_irq.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

@@ -59,7 +59,7 @@ int radeon_enable_vblank(struct drm_device *dev, int crtc)
 	default:
 		DRM_ERROR("tried to enable vblank on non-existent crtc %d\n",
 			  crtc);
-		return EINVAL;
+		return -EINVAL;
 	}
 
 	return 0;

Looks good, Marcin. Andrew should probably just push it upstream.

Thanks,
Jesse