drm/i915/cnl: Fix PLL initialization for HDMI.

HDMI Mode selection on CNL is on CFGCR0 for that PLL, not
on in a global CTRL1 as it was on SKL.

The original patch addressed this difference, but leaving behind
this single entry here. So we were checking the wrong bits during
the PLL initialization and consequently avoiding the CFGCR1 setup
during HDMI initialization. Luckly when only HDMI was in use BIOS
had already setup this for us. But the dual display with hot plug
were messed up.

Fixes: a927c927 ("drm/i915/cnl: Initialize PLLs")
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Kahola, Mika <mika.kahola@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: James Ausmus <james.ausmus@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003220859.21352-3-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/intel_dpll_mgr.c

@@ -1996,7 +1996,7 @@ static void cnl_ddi_pll_enable(struct drm_i915_private *dev_priv,
 
 	/* 3. Configure DPLL_CFGCR0 */
 	/* Avoid touch CFGCR1 if HDMI mode is not enabled */
-	if (pll->state.hw_state.cfgcr0 & DPLL_CTRL1_HDMI_MODE(pll->id)) {
+	if (pll->state.hw_state.cfgcr0 & DPLL_CFGCR0_HDMI_MODE) {
 		val = pll->state.hw_state.cfgcr1;
 		I915_WRITE(CNL_DPLL_CFGCR1(pll->id), val);
 		/* 4. Reab back to ensure writes completed */