drm/i915/skl: Make gen8_irq_power_well_post_enable() take a pipe mask

While we only need to restore pipe B/C interrupt registers on BDW when
enabling the power well, skylake a bit more flexible and we'll also need
to restore the pipe A registers as it has its own power well that can be
toggled.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 6d8e29a..35e0cb6 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -195,7 +195,8 @@
 	vga_put(dev->pdev, VGA_RSRC_LEGACY_IO);
 
 	if (IS_BROADWELL(dev) || (INTEL_INFO(dev)->gen >= 9))
-		gen8_irq_power_well_post_enable(dev_priv);
+		gen8_irq_power_well_post_enable(dev_priv,
+						1 << PIPE_C | 1 << PIPE_B);
 }
 
 static void hsw_set_power_well(struct drm_i915_private *dev_priv,