[Intel-gfx] All sort of cdclk stuff

[Mika Kahola]

This patch series rebases Ville's original cdclk patch series

http://lists.freedesktop.org/archives/intel-gfx/2014-November/055633.html

The patches include modifications to

  drm/i915: Return more precise cdclk for gen2/3
  drm/i915: Fix i855_get_display_clock_speed()
  drm/i915: Fix 852GM/GMV cdclk
  drm/i915: Add cdclk extraction for g33, 965gm and g4x
  drm/i915: ILK cdclk seems to be 450MHz
  drm/i915: Assume 400 MHz cdclk for the rest of gen4-7
  drm/i915: Simplify ilk_get_aux_clock_divider()
  drm/i915: Convert the ddi cdclk code to .get_display_clock_speed()
  drm/i915: Warn when cdclk for the platforms is not known
  drm/i915: Cache the current cdclk frequency in dev_priv
  drm/i915: Use cached cdclk value
  drm/i915: Unify ilk and hsw .get_aux_clock_divider()
  drm/i915: Store max cdclk value in dev_priv
  drm/i915: Don't enable IPS when pixel rate exceeds 95% of cdclk
  drm/i915: Fix chv cdclk support
  drm/i915: HSW cdclk change support
  drm/i915: Add IS_BDW_ULX()
  drm/i915: BDW cdclk change support
  drm/i915: Limit CHV max cdclk to 320 MHz
  drm/i915: Combined VLV, HSW, and BDW global pipe conf into single function
            'intel_modeset_global_pipes()'

-- 
Mika Kahola, Intel OTC