drm/i915: clean up Hz to PWM for i965

Unify function structure as any other *_hz_to_pwm() functions are
structured.

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481616169-16210-4-git-send-email-mika.kahola@intel.com

drivers/gpu/drm/i915/intel_panel.c

@@ -1327,8 +1327,7 @@ static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
  */
 static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 {
-	struct drm_device *dev = connector->base.dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 	int clock;
 
 	if (IS_G4X(dev_priv))