drm/i915: PLL macro cleanup and pipe assertion check

Add a macro for accessing the two pipe PLLs and add a check to make sure
we don't access a non-existent one in the enable/disable functions.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-By: Eugeni Dodonov <eugeni.dodonov@intel.com>
Reviewed-By: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2e28c68..dade95c 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1172,6 +1172,9 @@
 	int reg;
 	u32 val;
 
+	if (pipe > 1)
+		return;
+
 	/* PCH only available on ILK+ */
 	BUG_ON(dev_priv->info->gen < 5);
 
@@ -1192,6 +1195,9 @@
 	int reg;
 	u32 val;
 
+	if (pipe > 1)
+		return;
+
 	/* PCH only available on ILK+ */
 	BUG_ON(dev_priv->info->gen < 5);