drm/i915/de: Have intel_de_wait() hand out the final register value

drm/i915/de: Have intel_de_wait() hand out the final register value

We currently have a bunch of places that want the final register
value after register polling. Currently those places are mostly
using intel_de_wait_custom(). That is not a function that we
want to keep around as it pretty much prevents conversion to
poll_timeout_us().

Have intel_de_wait() also return the final register value so
that some of the current users can be converted over to the
simpler interface.

Done with cocci:
@@
@@
int intel_de_wait(...
+ ,u32 *out_value
 )
{
...
__intel_wait_for_register(...,
- NULL
+ out_value
 )
...
}

@@
@@
 intel_de_wait(...
+ ,NULL
 )

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251110172756.2132-3-ville.syrjala@linux.intel.com
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>