The 32 bit sched_clock interface now supports 64 bits. Upgrade to
the 64 bit function to allow us to remove the 32 bit registration
interface.

Cc: Soren Brinkmann <soren.brinkmann@xilinx.com>
Cc: Michal Simek <monstr@monstr.eu>
Tested-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>