rtc-ds1307: remove legacy probe() checks

Remove RTC register value checks from the rtc-ds1307 probe() function.
They were left over from the legacy style I2C driver, which had to defend
against finding a non-RTC chip when the driver was probed.

Also fix a minor glitch in the alarm support: DS1307 chips don't have
alarms, so name those methods after one of the chips which actually *do*
have alarms (DS1337).

Signed-off-by: Jüri Reitel <juri.reitel@liewenthal.ee>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Sebastien Barre <sbarre@sdelcc.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Jean Delvare <khali@linux-fr.org>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>