tty: serial: 8250_mtk: remove unnecessary test

When the driver has probed successfully the clk pointer is always valid,
so no need to test for it.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed