pwm: jz4740: Add trailing \n to error messages

Error messages are supposed to end in \n. Add the line terminator to the
two error messages that lack this.

Suggested-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>