ASoC: rockchip-max98090: Fix NULL pointer dereference while accessing to jack.

Commit f2ed6b07

 ("ASoC: Make aux_dev more like a generic
component") caused a regression on this driver, since now a
kernel oops is seen when rockchip-mac98090 driver is loaded.

That commit changed the probing of aux_devs before checking
new DAI links, so for this driver rk_98090_headset_init is
called before rk_init and then the kernel oops due a NULL
pointer dereference inside rk_98090_headset_init function
since there is a call that tries to access the jack pointer
which has not been allocated yet.

This is the call chain that causes the crash:

 rk_98090_headset_init
   -> ts3a227e_enable_jack_detect
      -> snd_jack_set_key
 rk_init
   -> snd_soc_card_jack_new

This patch moves the new jack object creation from rk_init
to rk_98090_headset_init function making sure the jack is
created before is accessed.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>