minigbm: i915: make Y-tiling default

Y-tiling should be the default case, unless the user
explicitly asks for:

(1) a linear buffer
(2) frequent SW access
(3) a scanout buffer

BUG=None
TEST=None
CQ-DEPEND=CL:392547

Change-Id: I6b7751f28c7127a458cc754bc2114ea1dad7a80c
Reviewed-on: https://chromium-review.googlesource.com/398425
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 cc27121..f2efadc 100644
--- a/i915.c
+++ b/i915.c
@@ -135,8 +135,7 @@
 		tiling_mode = I915_TILING_NONE;
 	else if (flags & DRV_BO_USE_SCANOUT)
 		tiling_mode = I915_TILING_X;
-	else if (flags & (DRV_BO_USE_RENDERING | DRV_BO_USE_SW_READ_RARELY |
-			  DRV_BO_USE_SW_WRITE_RARELY))
+	else
 		tiling_mode = I915_TILING_Y;
 
 	i915_align_dimensions(drv, tiling_mode, &width, &height, bpp);