Rather than using DaVinci specific davinci_soc_info based
restart hook, use the restart hook available in the machine
descriptor instead.

Tested on DM365 and AM18x EVMs.

v2:
Changed to use restart hook in machine descriptor
per Russell's comment.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>