drivers/rtc/rtc-s3c.c: remove NO_IRQ macro

NO_IRQ may be defined as '(unsigned int) -1' in some architectures (arm,
sh ...), and either may not be defined in some architectures (arm64) which
can enable RTC_DRV_S3C.

Also since platform_get_irq returns err-code in case of any error, we do
not need to intialize s3c_rtc_alarmno and s3c_rtc_tickno.

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>