With jackpoll_interval != 0, it's used to poll jack event periodically
in a delayed work. if it's 0, give the caller chance to probe jack status
but will not restart the delayed work.

In the next patch which enable WAKEEN feature, HDA controller was able to wake
up system when it's in D3, it's useful to detect Jack hotplug event and notify
userspace. By default the jackpoll_interval=0, this patch let jack poll once
without starting the delayed work.
Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>