audio: add wakelock capability for audiohalservice

1. wake_lock group
2. BLOCK_SUSPEND capability

int pm_wake_lock(const char *buf)
{
	const char *str = buf;
	struct wakelock *wl;
	u64 timeout_ns = 0;
	size_t len;
	int ret = 0;

	if (!capable(CAP_BLOCK_SUSPEND))
		return -EPERM;
Bug: 111018819
Test: manual
Change-Id: I1283e4b1ab2b95e4e94df045240001485593f1ab
Signed-off-by: Carter Hsu <carterhsu@google.com>