drm/i915: Introduce intel_set_rps()

Replace the valleyview_set_rps() and gen6_set_rps() calls with
intel_set_rps() which itself does the IS_VALLEYVIEW() check. The
code becomes simpler since the callers don't have to do this check
themselves.

Most of the change was performe with the following semantic patch:
@@
expression E1, E2, E3;
@@
- if (IS_VALLEYVIEW(E1)) {
-  valleyview_set_rps(E2, E3);
- } else {
-  gen6_set_rps(E2, E3);
- }
+ intel_set_rps(E2, E3);

Adding intel_set_rps() and making valleyview_set_rps() and gen6_set_rps()
static was done manually. Also valleyview_set_rps() had to be moved a
bit avoid a forward declaration.

v2: Use a less greedy semantic patch

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
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/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d8b4d0a..b6b02f3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3183,8 +3183,7 @@
 extern void i915_redisable_vga_power_on(struct drm_device *dev);
 extern bool ironlake_set_drps(struct drm_device *dev, u8 val);
 extern void intel_init_pch_refclk(struct drm_device *dev);
-extern void gen6_set_rps(struct drm_device *dev, u8 val);
-extern void valleyview_set_rps(struct drm_device *dev, u8 val);
+extern void intel_set_rps(struct drm_device *dev, u8 val);
 extern void intel_set_memory_cxsr(struct drm_i915_private *dev_priv,
 				  bool enable);
 extern void intel_detect_pch(struct drm_device *dev);