UPSTREAM: x86: serial: Add a coreboot serial driver

Coreboot can provide information about the serial device in use on a
platform. Add a driver that uses this information to produce a working
UART.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
(cherry picked from commit 44482e8a2a33835563c17d49dac4004d4da0a7ea)
Change-Id: I343b342191cff828d28450bbb27188594f80ab8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/u-boot/+/2113272
Reviewed-by: Raul E Rangel <rrangel@chromium.org>
3 files changed