libgralloc: Set the Adreno raster mode as "unknown"

Set the raster mode as "unknown" when calling libadreno_utils to
compute the surface stride. This allows libadreno_utils to decide
the best stride to pick up based on the specific GPU.

Change-Id: Id88f5887168564398492ab03d160ddd0ce5e083a
diff --git a/libgralloc/alloc_controller.cpp b/libgralloc/alloc_controller.cpp
index c697cf8..4f2acbc 100644
--- a/libgralloc/alloc_controller.cpp
+++ b/libgralloc/alloc_controller.cpp
@@ -120,7 +120,7 @@
         }
         if ((libadreno_utils) && (LINK_adreno_compute_padding)) {
             int surface_tile_height = 1;   // Linear surface
-            int raster_mode         = 1;   // Adreno TW raster mode.
+            int raster_mode         = 0;   // Adreno unknown raster mode.
             int padding_threshold   = 512; // Threshold for padding surfaces.
             // the function below expects the width to be a multiple of
             // 32 pixels, hence we pass stride instead of width.