drivers/rtc/rtc-twl.c: use devm_*() functions

Use devm_*() functions to make cleanup paths simpler, and remove
unnecessary remove().

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>