asahi: Guard for overflow when packing

I'm not convinced this is right.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11718>

src/gallium/drivers/asahi/agx_state.c

@@ -955,6 +955,7 @@ agx_build_pipeline(struct agx_context *ctx, struct agx_compiled_shader *cs, enum
    /* There is a maximum number of half words we may push with a single
     * BIND_UNIFORM record, so split up the range to fit. We only need to call
     * agx_push_location once, however, which reduces the cost. */
+   unsigned unif_records = 0;
 
    for (unsigned i = 0; i < cs->info.push_ranges; ++i) {
       struct agx_push push = cs->info.push[i];
@@ -962,6 +963,10 @@ agx_build_pipeline(struct agx_context *ctx, struct agx_compiled_shader *cs, enum
       unsigned halfs_per_record = 14;
       unsigned records = DIV_ROUND_UP(push.length, halfs_per_record);
 
+      /* Ensure we don't overflow */
+      unif_records += records;
+      assert(unif_records < 16);
+
       for (unsigned j = 0; j < records; ++j) {
          agx_pack(record, BIND_UNIFORM, cfg) {
             cfg.start_halfs = push.base + (j * halfs_per_record);