Move all jack-detect initialization to rt5651_set_jack_detect. The main
reason to do this is so that platform code can setup jack-detect properties
after the device has been probed, which unfortunately is necessary on some
platforms.

This has 2 additional advantages:
1) Grouping all jack-detect init together makes it easier to follow what
is happening and results in a small reduction in the number of loc.
2) Before we would register the irq handler before rt5651->hp_jack was
assigned, leading to a potential NULL deref if the jack_detect work runs
before the machine driver has called set_jack.
Tested-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Brown <broonie@kernel.org>