pwm: qti-lpg: change to use u64 data type for calculation

Change to use the u64 data type for multiplication and division so that
there is no need to check the overflow.

Change-Id: I4aca3afac1056fb304728cc9fb04d97056919223
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>
1 file changed