gallium/cso: avoid unnecessary null dereference

The label `out:` calls `destroy()` which dereferences `ctx`.
This is unnecessary as there is nothing to destroy.
Immediately return instead.

CovID: 1258255
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/auxiliary/cso_cache/cso_context.c

@@ -251,7 +251,7 @@ struct cso_context *cso_create_context( struct pipe_context *pipe )
 {
    struct cso_context *ctx = CALLOC_STRUCT(cso_context);
    if (!ctx)
-      goto out;
+      return NULL;
 
    ctx->cache = cso_cache_create();
    if (ctx->cache == NULL)