[ARM] 4491/1: em7210 rtc clock

The commit d815461c in linus tree
converts the rtc-rs5c372 driver to a "new style" i2c driver.
Like commit c00593f6

, this patch
register the rtc i2c device for the em7210 board.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>