ARM: 7945/1: footbridge: Switch to sched_clock_register()

The 32 bit sched_clock interface supports 64 bits since 3.13-rc1.
Upgrade to the 64 bit function to allow us to remove the 32 bit
registration interface.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>