mb/siemens/{mc_apl3,mc_apl5,mc_apl6}: Remove TX_DWORD3 macro

A correction of Tx signal from SATA interface is not necessary on these
boards currently. Therefore remove the define and the corresponding code
on mc_apl5.

Change-Id: I5092ee128cb35e126069d18bb3cbd635e01bbcdb
Signed-off-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76173
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jan Samek <jan.samek@siemens.com>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

src/mainboard/siemens/mc_apl1/variants/mc_apl3/mainboard.c

@@ -14,8 +14,6 @@
 #include <baseboard/variants.h>
 #include <types.h>
 
-#define TX_DWORD3	0xa8c
-
 void variant_mainboard_final(void)
 {
 	struct device *dev = NULL;

src/mainboard/siemens/mc_apl1/variants/mc_apl5/mainboard.c

@@ -13,8 +13,6 @@
 #include <baseboard/variants.h>
 #include <types.h>
 
-#define TX_DWORD3	0xa8c
-
 void variant_mainboard_final(void)
 {
 	struct device *dev = NULL;
@@ -34,11 +32,6 @@ void variant_mainboard_final(void)
 	 */
 	pcr_or32(PID_LPC, PCR_LPC_PRC, (PCR_LPC_CCE_EN | PCR_LPC_PCE_EN));
 
-	/* Correct the SATA transmit signal via the High Speed I/O Transmit Control Register 3.
-	   Bit [23:16] set the output voltage swing for TX line. The value 0x4a sets the swing
-	   level to 0.58 V. */
-	pcr_rmw32(PID_MODPHY, TX_DWORD3, (0x00 << 16), (0x4a << 16));
-
 	/* Set Master Enable for on-board PCI device if allowed. */
 	dev = dev_find_device(PCI_VID_SIEMENS, 0x403e, 0);
 	if (dev) {

src/mainboard/siemens/mc_apl1/variants/mc_apl6/mainboard.c

@@ -14,8 +14,6 @@
 #include <baseboard/variants.h>
 #include <types.h>
 
-#define TX_DWORD3	0xa8c
-
 void variant_mainboard_final(void)
 {
 	struct device *dev = NULL;