mb/siemens/mc_ehl8: Switch from LPSS UART to legacy 8250 I/O UART

Replace the memory-mapped LPSS UART2 with I/O port-mapped legacy
8250 UART for the serial console which is placed on mainboard.

- Removing INTEL_LPSS_UART_FOR_CONSOLE activates the
  DRIVERS_UART_8250IO switch by default.
- Change UART_FOR_CONSOLE from 2 to 0 (COM1 at I/O 0x3F8).
- Add SOC_INTEL_COMMON_BLOCK_LPC_COMB_ENABLE (to enable COM2 at I/O
  0x2F8).
- Sort Kconfig switches alphabetically.

TEST=Built and booted on mc_ehl8
- Verifed boot log on COM1.
- Verifed functionality in OS via:
1) stty -F /dev/ttySx 115200 cs8 -cstopb -parenb
2) sending: echo "teststring" > /dev/ttySx
3) receiving: cat /dev/ttySx

Change-Id: I72b2c0e745b40beab862ee3b68fdb6bfc54ed9ed
Signed-off-by: Uwe Poeche <uwe.poeche@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90767
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>

src/mainboard/siemens/mc_ehl/variants/mc_ehl8/Kconfig

@@ -4,13 +4,13 @@ if BOARD_SIEMENS_MC_EHL8
 
 config BOARD_SPECIFIC_OPTIONS
 	def_bool y
-	select DRIVERS_I2C_RV3028C7
-	select DRIVERS_I2C_PI608GP
 	select DRIVER_INTEL_I210
-	select INTEL_LPSS_UART_FOR_CONSOLE
+	select DRIVERS_I2C_PI608GP
+	select DRIVERS_I2C_RV3028C7
 	select NC_FPGA_POST_CODE
 	select MAINBOARD_HAS_TPM2
 	select MEMORY_MAPPED_TPM
+	select SOC_INTEL_COMMON_BLOCK_LPC_COMB_ENABLE
 	select TPM_MEASURED_BOOT
 	select TPM_MEASURED_BOOT_INIT_BOOTBLOCK
 
@@ -19,7 +19,7 @@ config FMDFILE
 
 config UART_FOR_CONSOLE
 	int
-	default 2
+	default 0
 
 config EARLY_PCI_BRIDGE_DEVICE
 	hex