ASoC: wcd9xxx: Avoid plug type re-determination

In the case where there is mechanical interrupt
at the same time when polling scheduled for execution,
we should make sure that if plug type is found and reported
by the polling, re-determination from the insertion irq
should be avoided. Add a check in the insertion irq before
proceeding further to determine the plug type.

Change-Id: I7af6c267da96f099b303bdf818382ed801faf520
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>