anv, iris: Set MediaSamplerDOPClockGateEnable for gen12+

anv, iris: Set MediaSamplerDOPClockGateEnable for gen12+

This has been shown to help performance on TGL and DG1. This could be
applied to gen9+, but we still need to show if it helps with those
platforms.

Rework:
 * Make change in src/intel/vulkan/genX_cmd_buffer.c too. (Ken)
 * Keep mask as 3 for gen < 12

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6684>