drm/i915: Fixup kerneldoc for intel_cdclk_needs_cd2x_update

drivers/gpu/drm/i915/intel_cdclk.c:2116: warning: Function parameter or member 'dev_priv' not described in 'intel_cdclk_needs_cd2x_update'
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Abhay Kumar <abhay.kumar@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190404073357.18795-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_cdclk.c

@@ -2104,6 +2104,7 @@ bool intel_cdclk_needs_modeset(const struct intel_cdclk_state *a,
 
 /**
  * intel_cdclk_needs_cd2x_update - Determine if two CDCLK states require a cd2x divider update
+ * @dev_priv: Not a CDCLK state, it's the drm_i915_private!
  * @a: first CDCLK state
  * @b: second CDCLK state
  *