util: Fix/silence variable shadowing warnings

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7552>

src/util/format/u_format.h

@@ -382,6 +382,9 @@ struct util_format_unpack_description {
 typedef void (*util_format_fetch_rgba_func_ptr)(void *dst, const uint8_t *src,
                                                 unsigned i, unsigned j);
 
+/* Silence warnings triggered by sharing function/struct names */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wshadow"
 const struct util_format_description *
 util_format_description(enum pipe_format format) ATTRIBUTE_CONST;
 
@@ -390,6 +393,7 @@ util_format_pack_description(enum pipe_format format) ATTRIBUTE_CONST;
 
 const struct util_format_unpack_description *
 util_format_unpack_description(enum pipe_format format) ATTRIBUTE_CONST;
+#pragma GCC diagnostic pop
 
 /**
  * Returns a function to fetch a single pixel (i, j) from a block.