ARM: local timers: convert MSM to runtime registration interface

Convert the MSM timers to the runtime registration interface.

Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: David Brown <davidb@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>