drm/radeon: Fix VRAM size calculation for VRAM >= 4GB

Add ULL prefix to avoid overflow.

Signed-off-by: Niels Ole Salscheider <niels_ole@salscheider-online.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 93f760e..6c0ce89 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -726,7 +726,7 @@
 		return r;
 	}
 	DRM_INFO("radeon: %uM of VRAM memory ready\n",
-		 (unsigned)rdev->mc.real_vram_size / (1024 * 1024));
+		 (unsigned) (rdev->mc.real_vram_size / (1024 * 1024)));
 	r = ttm_bo_init_mm(&rdev->mman.bdev, TTM_PL_TT,
 				rdev->mc.gtt_size >> PAGE_SHIFT);
 	if (r) {