drm/i915: s/intel_gen4_compute_page_offset/intel_compute_tile_offset/

Since intel_gen4_compute_page_offset() can now handle tiling formats
all the way down to gen2, rename it to intel_compute_tile_offset().
Not that we actually use it on gen2/3 since there's no DSPSURF etc.
registers which would take a page aligned address.

v2: s/page/tile/ (Daniel)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1452625717-9713-7-git-send-email-ville.syrjala@linux.intel.com
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 6aaaa8d..059b46e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1195,11 +1195,11 @@
 void assert_pipe(struct drm_i915_private *dev_priv, enum pipe pipe, bool state);
 #define assert_pipe_enabled(d, p) assert_pipe(d, p, true)
 #define assert_pipe_disabled(d, p) assert_pipe(d, p, false)
-unsigned long intel_gen4_compute_page_offset(struct drm_i915_private *dev_priv,
-					     int *x, int *y,
-					     uint64_t fb_modifier,
-					     unsigned int cpp,
-					     unsigned int pitch);
+unsigned long intel_compute_tile_offset(struct drm_i915_private *dev_priv,
+					int *x, int *y,
+					uint64_t fb_modifier,
+					unsigned int cpp,
+					unsigned int pitch);
 void intel_prepare_reset(struct drm_device *dev);
 void intel_finish_reset(struct drm_device *dev);
 void hsw_enable_pc8(struct drm_i915_private *dev_priv);