rtc: rtc-s3c: fix access unit from byte to word on RTCCON

S3C2410_RTCCON of TYPE_S3C64XX RTC should be read/written by readw and
writew, because TYPE_S3C64XX RTC uses bit 8 and 9.  And TYPE_S3C2410 RTC
also can access it by readw and writew.

[atul.dahiya@samsung.com: tested on smdk2416]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Changhwan Youn <chaos.youn@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Tested-by: Atul Dahiya <atul.dahiya@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Wan ZongShun <mcuos.com@gmail.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>