mfd: arizona: Factor out checking of jack detection state

Currently runtime_suspend will fully power off the codec if
the jack detection is not enabled. Not all future codecs will
have jack detection so to prepare for these codecs this patch
factors out the check so that it be called as needed in the
existing codec-specific switch cases.

Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>