msm: ipa: support pipe stats across multi-PDNS

When uses switch the internet PDN on android,
CNE will call the wan-driver ioctl to set
polling-interval as 0 and wan-driver should
reset the modem ipa counter to get accurate
pipe-stats across all PDNS.

Change-Id: I4b6b474b3b5f0db96f8f48a6242b476c92c03c36
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>