drm/i915/bxt: Add HW state verification for DDI PHY and CDCLK

I caught a few errors in our current PHY/CDCLK programming by sanity
checking the actual programmed state, so I thought it would be also
useful for the future. In addition to verifying the state after
programming it also verify it after exiting DC5, to make sure DMC
restored/kept intact everything related.

v2:
- Inlining __phy_reg_verify_state() doesn't make sense and also
  incorrect, so don't do it (PW/CI gcc)
v3:
- Rebase on latest -nightly

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: David Weinehall <david.weinehall@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459780030-15781-1-git-send-email-imre.deak@intel.com
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b9ed1b3..946b5df 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1924,6 +1924,7 @@
 	 * crappiness (can't read out DPLL_MD for pipes B & C).
 	 */
 	u32 chv_dpll_md[I915_MAX_PIPES];
+	u32 bxt_phy_grc;
 
 	u32 suspend_count;
 	bool suspended_to_idle;