msm: qmi: Initialize workqueue before it handles any events

The workqueue which handles any incoming events is initialized after the
clients of QMI interface module has registered for those events. Sometimes
the events get generated as soon as the registration is complete and
lead to accessing uninitialized workqueue.

Initialize the workqueue before the clients of QMI interface module
register for any events.

Change-Id: I8a2d0c5c631272a7941383d3715489f37aa2a4a9
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>