parisc: time: stop validating rtc_time in .read_time

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it just before returning from the callback.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>