drm/i915: Add HAS_PCH_LPT_H()

We have HAS_PCH_LPT_LP() already, so add HAS_PCH_LPT_H() and use it
where appropriate.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448893432-6978-4-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_panel.c

@@ -1308,7 +1308,7 @@ static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
 	else
 		mul = 128;
 
-	if (dev_priv->pch_id == INTEL_PCH_LPT_DEVICE_ID_TYPE)
+	if (HAS_PCH_LPT_H(dev_priv))
 		clock = MHz(135); /* LPT:H */
 	else
 		clock = MHz(24); /* LPT:LP */