RTC driver for DS1216 chips

RTC driver for Dallas/Maxim DS126 chips used in SNI RM200/RM400

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>