drm/i915: Replace "INTEL_INFO->gen == x" checks with IS_GENx

This way optimization from a previous patch works even better.

v2: Rebase.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 5d80a2b..1bb0f9a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2146,14 +2146,14 @@
 static void intel_fixup_spr_wm_latency(struct drm_device *dev, uint16_t wm[5])
 {
 	/* ILK sprite LP0 latency is 1300 ns */
-	if (INTEL_INFO(dev)->gen == 5)
+	if (IS_GEN5(dev))
 		wm[0] = 13;
 }
 
 static void intel_fixup_cur_wm_latency(struct drm_device *dev, uint16_t wm[5])
 {
 	/* ILK cursor LP0 latency is 1300 ns */
-	if (INTEL_INFO(dev)->gen == 5)
+	if (IS_GEN5(dev))
 		wm[0] = 13;
 
 	/* WaDoubleCursorLP3Latency:ivb */