drm/i915: s/PS_COEE_INDEX_AUTO_INC/PS_COEF_INDEX_AUTO_INC/

Fix a typo in the PS_COEF_INDEX_AUTO_INC define.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230426135019.7603-5-ville.syrjala@linux.intel.com