ASoC: rt5645: fix kernel hang when call rt5645_set_jack_detect()

rt5645_set_jack_detect() is usually called from
snd_soc_dai_link.init() and it calls snd_soc_jack_report() from
rt5645_irq_detection() if jack is inserted. snd_soc_jack_report()
results in kernel hang if it is called from a context which cannot
sleep.
This patch makes sure snd_soc_jack_report() is called from
workqueue. It can fix the kernel hang issue.

Signed-off-by: John Lin <john.lin@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>