rtc: kconfig: remove unnecessary dependencies.

Remove "depends on RTC_CLASS = y" for multiple Kconfig definitions, as all
of them are already placed under "if RTC_CLASS".

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>