lenovo/s230u: Add Thinkpad Twist (S230U)

Created using autoport plus some manual work and copying from G505S to
account for the non-H8 EC.

This model uses the same ENE KB9012 EC as the G505S.

Tested:
- Mainboard variant with 8GB Elpida DDR3
- SeaBIOS payload
- Booting into Linux 4.9.6 with Debian/unstable installed on the
  internal HDD/SDD slot
- Native raminit
- Both native VGA init and option rom VGA init
- Basic TPM functionality (auto-detection and RNG)
- Battery status readout
- Basic ACPI functions (power button event; power-off; reboot)
- thinkpad-acpi hotkey functions
- thinkpad-acpi LED control (red thinkpad LED)
- Suspend to RAM and resume works
- Mini displayport output works

Known issues:
- Patches needed for EC battery support
  https://review.coreboot.org/#/c/18348/
  https://review.coreboot.org/#/c/18349/
- No thermal zone since temperature sensing is not H8-compatible
  and needs to be reverse engineered.

Not tested:
- msata/wwan (probably works)

Signed-off-by: Tobias Diedrich <ranma+coreboot@tdiedrich.de>
Change-Id: I52bc4515277e5c18afbb14a80a9ac788049f485c
Reviewed-on: https://review.coreboot.org/18351
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
diff --git a/src/mainboard/lenovo/s230u/Kconfig.name b/src/mainboard/lenovo/s230u/Kconfig.name
new file mode 100644
index 0000000..61d1ab7
--- /dev/null
+++ b/src/mainboard/lenovo/s230u/Kconfig.name
@@ -0,0 +1,2 @@
+config BOARD_LENOVO_S230U
+	bool "ThinkPad S230U (Twist)"