drm/i915: Nuke skl_write_wm_level() and skl_ddb_entry_write()

Get rid of skl_ddb_entry_write() and skl_write_wm_level() and
just call intel_de_write_fw() directly.

This is prep work towards DSB based plane updates where these
wrappers are more of a hinderance.

Done with cocci mostly:
@@
expression D, R, L;
@@
- skl_write_wm_level(D, R, L)
+ intel_de_write_fw(D, R, skl_plane_wm_reg_val(L))

@@
expression D, R, B;
@@
- skl_ddb_entry_write(D, R, B)
+ intel_de_write_fw(D, R, skl_plane_ddb_reg_val(B))

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240510152329.24098-16-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>