Change in coreboot[master]: soc/intel/skylake: Enable UART debug port in bootblock always

[Furquan Shaikh (Code Review)]

Hello build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/20835

to look at the new patch set (#2).

Change subject: soc/intel/skylake: Enable UART debug port in bootblock always
......................................................................

soc/intel/skylake: Enable UART debug port in bootblock always

Irrespective of whether UART_DEBUG is enabled in coreboot or not,
always enable UART controller for the debug port. This is required
because: UART hardware loses power while the system is
suspended. Linux kernel does not re-initialize the UART controller on
resume and so when serial console is enabled in kernel, it can result
in hangs on resume from S3. On platforms like baytrail, this was
handled in a similar way by initializing UART controller on
resume(https://chromium-review.googlesource.com/188011). In this
change, UART is always initialized in bootblock irrespective of normal
or S3 resume flow in order to re-use the UART drivers that are already
implemented and avoid redundancy.

BUG=b:64030366
TEST=Verified that kernel does not hang with the following sequence:
echo 'N' > /sys/module/printk/parameters/console_suspend
echo mem > /sys/power/state
<Resume from S3>

Change-Id: Ic936ac2a787fdc83935103c3ce4ed8f124a97a89
Signed-off-by: Furquan Shaikh 
---
M src/soc/intel/skylake/Kconfig
M src/soc/intel/skylake/Makefile.inc
M src/soc/intel/skylake/bootblock/bootblock.c
M src/soc/intel/skylake/bootblock/uart.c
4 files changed, 7 insertions(+), 8 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/35/20835/2