libagx: mask counters to 32-bit

possibly we should use real 64-bit counters, that's something for later though.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30382>

src/asahi/lib/shaders/query.cl

@@ -10,6 +10,9 @@
 static inline void
 write_query_result(uintptr_t dst_addr, int32_t idx, bool is_64, uint64_t result)
 {
+   /* TODO: do we want real 64-bit stats? sync with CPU impl */
+   result &= 0xffffffff;
+
    if (is_64) {
       global uint64_t *out = (global uint64_t *)dst_addr;
       out[idx] = result;