[ARM] 3610/1: Make reboot work on Versatile

Patch from Deepak Saxena

This patch makes soft reboot work on the Versatile board. Thanks to
Catalin Marinas @ ARM for pointing out the proper way to do this.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>