drm/i915: add lpt_init_pch_refclk

We need this code to init the PCH SSC refclk and the FDI registers.
The BIOS does this too and that's why VGA worked before this patch,
until you tried to suspend the machine...

This patch implements the "Sequence to enable CLKOUT_DP for FDI usage
and configure PCH FDI/IO" from our documentation.

v2:
- Squash Damien Lespiau's reset spelling fix on top.
- Add a comment that we don't need to bother about the ULT special
  case Damien noticed, since ULT won't have VGA.
- Add a comment to rip out the SDV codepaths once haswell ships for
  real.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> (v1)
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 8513e1c..65213bc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1662,7 +1662,7 @@
 extern bool intel_fbc_enabled(struct drm_device *dev);
 extern void intel_disable_fbc(struct drm_device *dev);
 extern bool ironlake_set_drps(struct drm_device *dev, u8 val);
-extern void ironlake_init_pch_refclk(struct drm_device *dev);
+extern void intel_init_pch_refclk(struct drm_device *dev);
 extern void gen6_set_rps(struct drm_device *dev, u8 val);
 extern void intel_detect_pch(struct drm_device *dev);
 extern int intel_trans_dp_port_sel(struct drm_crtc *crtc);