lenovo/t420: Add new port

This is based on t420s. Tested on a T420 without discrete GPU.
There is no support for nvidia gpu and optimus.

Signed-off-by: Nicolas Reinecke <nr@das-labor.org>
Tested-by: Iru Cai <mytbk920423@gmail.com>
Change-Id: Ie9405966e56180ac1c43a3c5b83181ee500177c8
Reviewed-on: https://review.coreboot.org/11765
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/mainboard/lenovo/t420/Kconfig.name b/src/mainboard/lenovo/t420/Kconfig.name
new file mode 100644
index 0000000..75570ad
--- /dev/null
+++ b/src/mainboard/lenovo/t420/Kconfig.name
@@ -0,0 +1,2 @@
+config BOARD_LENOVO_T420
+	bool "ThinkPad T420"