drm/audio: make drm_audio_component.h self-contained

The file uses bool and struct completion, include the relevant headers.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221123130932.3863985-1-jani.nikula@intel.com