serial: omap-serial: Move info message to probe function

Currently the info message about a missing wakeirq for uart is printed
every time the serial driver's startup function is called. This happens
multiple times and not just once.

This patch moves the infomessage to the probe function to display it
only once.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>