msm: ipa: wake up rmnet_ipa Tx queue explicitly

When rmnet_ipa is temporarily unable to send packets
it stops the Tx queue. Upon resuming, rmnet_ipa calls
netif_start_queue. This function only updates the status
of the queue but doesn't start it actually (until the next
packet to be sent is received into that queue). This causes
the previous packet to be stuck at the queue.
Instead, netif_wake_queue is used to trigger the queue to
invoke the xmit function immediately.
Note that netif_wake_queue is called from a workqueue context
and not from RM context.

CRs-fixed: 765957
Change-Id: I4afc3b59b0d617b56984f03d7ca08235757dc5c9
Signed-off-by: Sivan Reinsten <sivanr@codeaurora.org>
Acked-by: David Arinzon <darinzon@qti.qualcomm.com>