drm/i915: s/need_cd2x_updare/can_cd2x_update/

intel_cdclk_needs_cd2x_update() is named rather confusingly.
We don't have to do a cd2x update, rather we are allowed to
do one (as opposed to a full PLL reprogramming with its heavy
handed modeset). So let's rename the function to
intel_cdclk_can_cd2x_update().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200120174728.21095-7-ville.syrjala@linux.intel.com


Reviewed-by: Imre Deak <imre.deak@intel.com>