aubinator: Fix compiler warning

Add 'const' qualifier to gen_field_iterator::p pointer (Ken)

Signed-off-by: Sirisha Gandikota <Sirisha.Gandikota@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/intel/tools/decoder.h

@@ -47,7 +47,7 @@ struct gen_field_iterator {
    struct gen_group *group;
    const char *name;
    char value[128];
-   uint32_t *p;
+   const uint32_t *p;
    int i;
 };