drm/i915: Rename intel_flush_display_plane to intel_flush_primary_plane

The intel_flush_primary_plane name actually tells us which plane
we're talking about.

Also reorganize the internals a bit and add a missing POSTING_READ()
to make sure the hardware has seen the changes by the time we
return from the function.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index d61aec2..18c4062 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1094,7 +1094,7 @@
 		unsigned int xsize, ysize;
 		/* Pipe must be off here */
 		I915_WRITE(dspcntr_reg, dspcntr & ~DISPLAY_PLANE_ENABLE);
-		intel_flush_display_plane(dev_priv, intel_crtc->plane);
+		intel_flush_primary_plane(dev_priv, intel_crtc->plane);
 
 		/* Wait for vblank for the disable to take effect */
 		if (IS_GEN2(dev))
@@ -1123,7 +1123,7 @@
 
 		I915_WRITE(pipeconf_reg, pipeconf);
 		I915_WRITE(dspcntr_reg, dspcntr);
-		intel_flush_display_plane(dev_priv, intel_crtc->plane);
+		intel_flush_primary_plane(dev_priv, intel_crtc->plane);
 	}
 
 	j = 0;