ASoC: codecs: rt298: Set component to NULL on remove

Make sure that component is set to proper value, otherwise we may
dereference freed component in interrupt.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220707125701.3518263-5-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>