drm/i915/cnl: Fix _CNL_PORT_TX_DW2_LN0_F definition.

This was wrong since its introduction on commit '04416108
("drm/i915/cnl: Add registers related to voltage swing sequences.")'

But since no Port F was needed so far we don't need to
propagate fixes back there.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180129232223.766-4-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -1964,7 +1964,7 @@ enum i915_power_well_id {
 #define _CNL_PORT_TX_DW2_LN0_B		0x162648
 #define _CNL_PORT_TX_DW2_LN0_C		0x162C48
 #define _CNL_PORT_TX_DW2_LN0_D		0x162E48
-#define _CNL_PORT_TX_DW2_LN0_F		0x162A48
+#define _CNL_PORT_TX_DW2_LN0_F		0x162848
 #define CNL_PORT_TX_DW2_GRP(port)	_MMIO_PORT6(port, \
 						    _CNL_PORT_TX_DW2_GRP_AE, \
 						    _CNL_PORT_TX_DW2_GRP_B, \