qcom: qnovo: restart pulse train in stall state

There are a couple of cases where qnovo charging fails,

1. pulse train enable command register fails to write through, or
2. pulse engine fails to start and pulse train timer PTTIME does
   not start counting.

In either case, qnovo charging will stop. Here is the fix,

Write register twice when enabling pulse train, and
restart pulse train if PTTIME does not increase.

Change-Id: Ic235f8f2bc67fe577e42848ef623870c25b68256
Signed-off-by: Harry Yang <harryy@codeaurora.org>
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>