drm/i915: adjust sprite base address

Just like in:

commit c2c75131244507c93f812862fdbd4f3a37139401
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jul 5 12:17:30 2012 +0200

    drm/i915: adjust framebuffer base address on gen4+

but this time, for the sprite planes. This ensures that the
sprite offset are always inside the supported hardware limits since it
becomes the offset into a page and we adjust the base address to a page
boundary.

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_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5d9b650..1096066 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1955,9 +1955,9 @@
 
 /* Computes the linear offset to the base tile and adjusts x, y. bytes per pixel
  * is assumed to be a power-of-two. */
-static unsigned long gen4_compute_dspaddr_offset_xtiled(int *x, int *y,
-							unsigned int bpp,
-							unsigned int pitch)
+unsigned long intel_gen4_compute_offset_xtiled(int *x, int *y,
+					       unsigned int bpp,
+					       unsigned int pitch)
 {
 	int tile_rows, tiles;
 
@@ -2029,9 +2029,9 @@
 
 	if (INTEL_INFO(dev)->gen >= 4) {
 		intel_crtc->dspaddr_offset =
-			gen4_compute_dspaddr_offset_xtiled(&x, &y,
-							   fb->bits_per_pixel / 8,
-							   fb->pitches[0]);
+			intel_gen4_compute_offset_xtiled(&x, &y,
+							 fb->bits_per_pixel / 8,
+							 fb->pitches[0]);
 		linear_offset -= intel_crtc->dspaddr_offset;
 	} else {
 		intel_crtc->dspaddr_offset = linear_offset;
@@ -2118,9 +2118,9 @@
 
 	linear_offset = y * fb->pitches[0] + x * (fb->bits_per_pixel / 8);
 	intel_crtc->dspaddr_offset =
-		gen4_compute_dspaddr_offset_xtiled(&x, &y,
-						   fb->bits_per_pixel / 8,
-						   fb->pitches[0]);
+		intel_gen4_compute_offset_xtiled(&x, &y,
+						 fb->bits_per_pixel / 8,
+						 fb->pitches[0]);
 	linear_offset -= intel_crtc->dspaddr_offset;
 
 	DRM_DEBUG_KMS("Writing base %08X %08lX %d %d %d\n",