drivers/rtc/rtc-twl.c: enable RTC irrespective of its prior state

As part of probe, before enabling RTC, RTC_CTRL register is read to check
if it is already running.  If RTC is used by kernel alone, then this read
is not required.  Even if RTC was enabled already by boot loader, setting
STOP_RTC bit again should not harm.  Hence removed unwanted read
operation.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.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>