iris/icl+: Report same caching domain as main surface for clear color BO.

iris/icl+: Report same caching domain as main surface for clear color BO.

Even though the clear color BO is bound as a read-only buffer, report
the same caching domain as the main BO in use_surface() (typically
IRIS_DOMAIN_RENDER_WRITE) in order to avoid ping-ponging back and
forth between IRIS_DOMAIN_RENDER_WRITE and IRIS_DOMAIN_OTHER_READ,
which leads to increased stall-at-pixel-scoreboard synchronization
between draw calls.

Fixes a 5%-10% FPS regression in some benchmarks spotted on ICL.

Reported-by: Clayton Craft <clayton.a.craft@intel.com>
Fixes: eb5d1c27227302167d299 "iris: Annotate all BO uses with domain and sequence number information."
Closes: #3097
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5411>