[Intel-gfx] All sort of cdclk stuff

[Mika Kahola]

This patch series rebases Ville's original cdclk patch series
excluding the ones that	have been reviewed.

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

The patches include modifications to

  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: 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: 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: Modeset global_pipes() update