r600g: silence a few valgrind warnings

src/gallium/winsys/r600/drm/r600_drm.c

@@ -67,7 +67,7 @@ unsigned r600_get_clock_crystal_freq(struct radeon *radeon)
 
 static int radeon_get_device(struct radeon *radeon)
 {
-	struct drm_radeon_info info;
+	struct drm_radeon_info info = {};
 	int r;
 
 	radeon->device = 0;

src/gallium/winsys/r600/drm/r600_hw_context.c

@@ -1088,7 +1088,7 @@ void r600_context_draw(struct r600_context *ctx, const struct r600_draw *draw)
 
 void r600_context_flush(struct r600_context *ctx)
 {
-	struct drm_radeon_cs drmib;
+	struct drm_radeon_cs drmib = {};
 	struct drm_radeon_cs_chunk chunks[2];
 	uint64_t chunk_array[2];
 	unsigned fence;

src/gallium/winsys/r600/drm/radeon_bo.c

@@ -98,7 +98,7 @@ struct radeon_bo *radeon_bo(struct radeon *radeon, unsigned handle,
 		bo->size = open_arg.size;
 		bo->shared = TRUE;
 	} else {
-		struct drm_radeon_gem_create args;
+		struct drm_radeon_gem_create args = {};
 
 		args.size = size;
 		args.alignment = alignment;
@@ -204,7 +204,7 @@ int radeon_bo_get_tiling_flags(struct radeon *radeon,
 			       uint32_t *tiling_flags,
 			       uint32_t *pitch)
 {
-	struct drm_radeon_gem_get_tiling args;
+	struct drm_radeon_gem_get_tiling args = {};
 	int ret;
 
 	args.handle = bo->handle;