msm: ipa: Fix to QMI initialization and polling state

Using a workqueue for initializing QMI functionality
can result in race conditions with cleanup operation
during SSR handling because of scheduling delays.
Make a change to not to use workqueue and initialize
the QMI functionality as part of probe itself.
For polling state, there is a possibility that pipe is
disconnected during switch between poll mode interrupt
mode. This can result in queueing switch_to_intr_work
work multiple times till the pipe is connected and there
is some activity. Make a change to check if the ep is
valid before queuing the work.

Change-Id: Id5a5128edb379308fa91b53062b6773af1b6de18
Acked-by: Chaitanya Pratapa <cpratapa@qti.qualcomm.com>
Signed-off-by: Sridhar Ancha <sancha@codeaurora.org>