msm ipa: wan driver fix DL SKB protocol

Previous DL SKB packets protocol is set wrong and
causing QMAP flow dissectors to fail within the
kernel as well as analysis tools to be unable to
parse QMAP streams. The fix is to change protocol
to right format as htons(ETH_P_MAP).

Change-Id: I3ea03472ea78d857528ebb5f5b57e413f3763d16
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>