drm/i915/casf: rename *_coef*() into *_coeff*()

drm/i915/casf: rename *_coef*() into *_coeff*()

Stick to the notion of already used *_coeff*() instead of *_coef*().
Rename that way convert_sharpness_coef_binary() and
intel_casf_scaler_compute_coef().

v1->v2
- rename intel_casf_scaler_compute_coef()

Cc: Nemesa Garg <nemesa.garg@intel.com>
Signed-off-by: Michał Grzelak <michal.grzelak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260509164048.627399-3-michal.grzelak@intel.com