msm: ipa: change ioctl about upstream wan iface

In order to provide more flexibility, CnE will provide
IPACM the UPstream network interface along with the tethered
network interface. Then usb/wlan client could have different
upstream PDNs.

Change-Id: Iba893b589d12c1a6387fa392d2568068bde4b4d4
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>