ASoC: codecs: rt298: Fix NULL jack in interrupt

Set rt298->jack to passed value in mic_detect, otherwise when jack is
set to NULL on next interrupt call, we may use freed pointer.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220707125701.3518263-2-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>