drm/i915/cdclk: Give the squash waveform length a name

Replace the slightly magic 'size = 16' with a bit more descriptive
name. We'll have another user for this value later on.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231128115138.13238-3-ville.syrjala@linux.intel.com


Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>