msm: pm-8x60: Use on_each_cpu instead of smp_call_function_many

The broadcast timer needs to be setup on all the online cores. As
smp_call_function_many doesn't execute the CPU invoking the call, switch
to using on_each_cpu. Also change the function prototype as it is called
only to turn on broadcast timers.

Change-Id: If7002d787d98b68cb229ebc40f3c817c5aefe1f1
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>