drivers/rtc/rtc-pcf8563.c: add device tree support

Set the of_match_table for this driver so that devices can be described
in the device tree.

Signed-off-by: Nick Bowler <nbowler@elliptictech.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>