minigbm: use drv_add_combination when adding a single combination

We defined the function, but it's since gone unused.

Change-Id: I23e7e57413c4a7c82d9da302b79e6b9c5068654d
Reviewed-on: https://chromium-review.googlesource.com/1229438
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
diff --git a/i915.c b/i915.c
index 3f62638..773fb69 100644
--- a/i915.c
+++ b/i915.c
@@ -185,9 +185,8 @@
 			     texture_use_flags);
 
 	/* Support y-tiled NV12 for libva */
-	const uint32_t nv12_format = DRM_FORMAT_NV12;
-	drv_add_combinations(drv, &nv12_format, 1, &metadata,
-			     BO_USE_TEXTURE | BO_USE_HW_VIDEO_DECODER);
+	drv_add_combination(drv, DRM_FORMAT_NV12, &metadata,
+			    BO_USE_TEXTURE | BO_USE_HW_VIDEO_DECODER);
 
 	kms_items = drv_query_kms(drv);
 	if (!kms_items)