serial: mvebu-uart: fix calculation of clock divisor

serial: mvebu-uart: fix calculation of clock divisor

commit 9078204ca5c33ba20443a8623a41a68a9995a70d upstream.

The clock divisor should be rounded to the closest value.

Signed-off-by: Pali Rohár <pali@kernel.org>
Fixes: db4ef1010c48 ("serial: mvebu-uart: add function to change baudrate")
Cc: stable@vger.kernel.org # 83363730a007 ("serial: mvebu-uart: clarify the baud rate derivation")
Link: https://lore.kernel.org/r/20210624224909.6350-2-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>