drivers/rtc/rtc-ds1343.c: add support of nvram for maxim dallas rtc ds1343

This is a patch to add support of nvram for maxim dallas rtc ds1343.

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@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>