msm: ipa: check for carrier state before queue wakeup

When USB is disconnected in the middle of data transfer
there is a possibility that tx queue will be waken up
as part of rndis_ipa_tx_complete_notify. Make change
to check for carrier state before waking up the queue.

Change-Id: Iecad09534c39871ca3d6bc75009772ae0c5b037d
Acked-by: Chaitanya Pratapa <cpratapa@qti.qualcomm.com>
Signed-off-by: Ravinder Konka <rkonka@codeaurora.org>