Small updates to make the RTC class Kconfig text be more informative.  This
should help folk used to the drivers/char/rtc.c support, or a single RTC, be
slightly less surprised by the differences.

Also, adds a new RTC_DEBUG option to predefine DEBUG in the framework and its
drivers, while debugging.  That's getting to be a standard idiom, and it's
pretty useful.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: NOleg Verych <olecom@flower.upol.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>