audio: add parameter for device shutdown notification

#include <cutils/log.h>

#include <cutils/str_parms.h>

/* Device state*/

#define AUDIO_PARAMETER_KEY_DEV_SHUTDOWN "dev_shutdown"

static s_audio_subsys audio_ss;

int audio_extn_pm_vote(void)

{

    int err, intfd, ret;

    FILE *fd;

    enum pm_event subsys_state;

    char halPropVal[PROPERTY_VALUE_MAX];

    bool prop_unload_image = false;