minigbm: standardize naming of map flags

It's helpful to differentiate map flags from normal buffer creation
flags. Note gralloc doesn't differentiate between map flags and buffer
creation flags. However, since flags are passed in with gralloc
(*lock)(), we can use a separate conversion function there.

BUG=chromium:764871
TEST=Boot Android and play games on Eve

Change-Id: Ic8aee84d9ac945abf93d9a9bda78fe3f77711cc3
Reviewed-on: https://chromium-review.googlesource.com/691424
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
diff --git a/gbm.c b/gbm.c
index f76e4ca..906560a 100644
--- a/gbm.c
+++ b/gbm.c
@@ -223,15 +223,16 @@
 }
 
 PUBLIC void *gbm_bo_map(struct gbm_bo *bo, uint32_t x, uint32_t y, uint32_t width, uint32_t height,
-			uint32_t flags, uint32_t *stride, void **map_data, size_t plane)
+			uint32_t transfer_flags, uint32_t *stride, void **map_data, size_t plane)
 {
+	uint32_t map_flags;
 	if (!bo || width == 0 || height == 0 || !stride || !map_data)
 		return NULL;
 
 	*stride = gbm_bo_get_plane_stride(bo, plane);
-	uint32_t drv_flags = flags & GBM_BO_TRANSFER_READ ? BO_TRANSFER_READ : BO_TRANSFER_NONE;
-	drv_flags |= flags & GBM_BO_TRANSFER_WRITE ? BO_TRANSFER_WRITE : BO_TRANSFER_NONE;
-	return drv_bo_map(bo->bo, x, y, width, height, drv_flags, (struct map_info **)map_data,
+	map_flags = (transfer_flags & GBM_BO_TRANSFER_READ) ? BO_MAP_READ : BO_MAP_NONE;
+	map_flags |= (transfer_flags & GBM_BO_TRANSFER_WRITE) ? BO_MAP_WRITE : BO_MAP_NONE;
+	return drv_bo_map(bo->bo, x, y, width, height, map_flags, (struct map_info **)map_data,
 			  plane);
 }