drm/i915: Use genX_ prefix for gt irq enable/disable functions

Traditionally we use genX_ for GT/render stuff and the codenames for
display stuff. But the gt and pm interrupt handling functions on
gen5/6+ stuck out as exceptions, so convert them.

Looking at the diff this nicely realigns our ducks since almost all
the callers are already platform-specific functions following the
genX_ pattern.

Spotted while reviewing some internal rps patches.

No function change in this patch.

Acked-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -3474,7 +3474,7 @@ static void gen8_enable_rps_interrupts(struct drm_device *dev)
 
 	spin_lock_irq(&dev_priv->irq_lock);
 	WARN_ON(dev_priv->rps.pm_iir);
-	bdw_enable_pm_irq(dev_priv, dev_priv->pm_rps_events);
+	gen8_enable_pm_irq(dev_priv, dev_priv->pm_rps_events);
 	I915_WRITE(GEN8_GT_IIR(2), dev_priv->pm_rps_events);
 	spin_unlock_irq(&dev_priv->irq_lock);
 }
@@ -3485,7 +3485,7 @@ static void gen6_enable_rps_interrupts(struct drm_device *dev)
 
 	spin_lock_irq(&dev_priv->irq_lock);
 	WARN_ON(dev_priv->rps.pm_iir);
-	snb_enable_pm_irq(dev_priv, dev_priv->pm_rps_events);
+	gen6_enable_pm_irq(dev_priv, dev_priv->pm_rps_events);
 	I915_WRITE(GEN6_PMIIR, dev_priv->pm_rps_events);
 	spin_unlock_irq(&dev_priv->irq_lock);
 }