soc/intel/skylake: Drop unreferenced PttSwitch dt setting

The value for this setting is not used anywhere. Drop it.

Change-Id: I75f6cdec6c69b374a07519bf9058b8f6e4916307
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48573
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/soc/intel/skylake/chip.h

@@ -299,8 +299,6 @@ struct soc_intel_skylake_config {
 	u8 ScsEmmcHs400RxStrobeDll1;
 	u8 ScsEmmcHs400TxDataDll;
 
-	u8 PttSwitch;
-
 	enum {
 		Display_iGFX,
 		Display_PEG,