soc/intel/common/uart: Refactor uart_common_init

1. Create a new function uart_lpss_init which takes the UART LPSS
controller out of reset and initializes and enables clock.

2. Instead of passing in m/n clock divider values as parameters to
uart_common_init, introduce Kconfig variables so that uart_lpss_init
can use the values directly without having to query the SoC.

BUG=b:64030366
TEST=Verified that UART still works on APL and KBL boards.

Change-Id: I74d01b0037d8c38fe6480c38ff2283d76097282a
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/20884
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

0 files changed, 0 insertions, 0 deletions