tty: serial: samsung_tty: Fix suspend/resume on S5L

We were restoring the IRQ masks then clearing them again, because
ucon_mask wasn't set properly. Adding that makes suspend/resume
work as intended.

Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20220502092505.30934-1-marcan@marcan.st


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>