vl/buffer: add sanity check after CALLOC_STRUCT

Check if we have successfully allocated memory.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

src/gallium/auxiliary/vl/vl_video_buffer.c

@@ -492,6 +492,8 @@ vl_video_buffer_create_ex2(struct pipe_context *pipe,
    unsigned i;
 
    buffer = CALLOC_STRUCT(vl_video_buffer);
+   if (!buffer)
+      return NULL;
 
    buffer->base = *tmpl;
    buffer->base.context = pipe;