mainboard/pcengines: select ADD_SEABIOS_SERCON_PORT_FILE

PC Engines boards are interfaced mainly via serial console.
Enable SeaBIOS serial console for these boards by default
when SeaBIOS selected as payload.

Change-Id: I9e65dd1e28859028c8c46f28a5442de8c59d4893
Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Reviewed-on: https://review.coreboot.org/27824
Tested-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/mainboard/pcengines/alix1c/Kconfig

@@ -14,6 +14,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select HAVE_OPTION_TABLE
 	select HAVE_CMOS_DEFAULT
 	select NO_EARLY_SMBUS
+	select SEABIOS_ADD_SERCON_PORT_FILE if PAYLOAD_SEABIOS
 
 config MAINBOARD_DIR
 	string

src/mainboard/pcengines/alix2d/Kconfig

@@ -11,6 +11,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select BOARD_ROMSIZE_KB_512
 	select POWER_BUTTON_FORCE_DISABLE
 	select NO_EARLY_SMBUS
+	select SEABIOS_ADD_SERCON_PORT_FILE if PAYLOAD_SEABIOS
 
 config MAINBOARD_DIR
 	string

src/mainboard/pcengines/apu1/Kconfig

@@ -30,6 +30,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select HAVE_CMOS_DEFAULT
 	select BOARD_ROMSIZE_KB_2048
 	select GENERIC_SPD_BIN
+	select SEABIOS_ADD_SERCON_PORT_FILE if PAYLOAD_SEABIOS
 
 config MAINBOARD_DIR
 	string

src/mainboard/pcengines/apu2/Kconfig

@@ -33,6 +33,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select GENERIC_SPD_BIN
 	select MAINBOARD_HAS_LPC_TPM
 	select MAINBOARD_HAS_TPM1
+	select SEABIOS_ADD_SERCON_PORT_FILE if PAYLOAD_SEABIOS
 
 config MAINBOARD_DIR
 	string