tty: serial: samsung: remove variable 'ufstat' set but not used

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/tty/serial/samsung_tty.c: In function s3c24xx_serial_rx_chars_dma:
drivers/tty/serial/samsung_tty.c:549:24: warning: variable ufstat set but not used [-Wunused-but-set-variable]

Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Link: https://lore.kernel.org/r/1574424258-138975-1-git-send-email-chenwandun@huawei.com


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