i965/surface_state: Emit the clear color address instead of value.

i965/surface_state: Emit the clear color address instead of value.

On Gen10, when emitting the surface state, use the value stored in the
clear color entry buffer by using a clear color address in the surface
state.

v4: Use the clear color offset from the clear_color_bo, when available.

Signed-off-by: Rafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>