ASoC: apq8084: Allow sharing of liquid dock plug interrupt

The dock plug detect GPIO is used as an interrupt indicating
when the Liquid device is attached to (or removed from) the
docking station. There may be other peripherals wanting to
register a handler for notification. Hence, allow this
interrupt to be shared by adding the IRQF_SHARED flag.

Change-Id: Ib018ba09d6b89c3784b544700878a366056a5221
Signed-off-by: Jack Pham <jackp@codeaurora.org>