intel/compiler: Silence unused parameter warning in brw_surface_payload_size

intel/compiler: Silence unused parameter warning in brw_surface_payload_size

src/intel/compiler/brw_eu_emit.c: In function ‘brw_surface_payload_size’:
src/intel/compiler/brw_eu_emit.c:3070:46: warning: unused parameter ‘p’ [-Wunused-parameter]
 3070 | brw_surface_payload_size(struct brw_codegen *p,
      |                          ~~~~~~~~~~~~~~~~~~~~^

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6826>