drm/i915/ehl: Add third combo PHY offset

v2: Rename register to _EHL_COMBOPHY_C.  (Jose)

Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190626000352.31926-3-matthew.d.roper@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -1793,8 +1793,10 @@ enum i915_power_well_id {
  */
 #define _ICL_COMBOPHY_A			0x162000
 #define _ICL_COMBOPHY_B			0x6C000
+#define _EHL_COMBOPHY_C			0x160000
 #define _ICL_COMBOPHY(port)		_PICK(port, _ICL_COMBOPHY_A, \
-					      _ICL_COMBOPHY_B)
+					      _ICL_COMBOPHY_B, \
+					      _EHL_COMBOPHY_C)
 
 /* CNL/ICL Port CL_DW registers */
 #define _ICL_PORT_CL_DW(dw, port)	(_ICL_COMBOPHY(port) + \