Bluetooth: ISO: Align broadcast sync_timeout with connection timeout

[ Upstream commit 42ed95de ]

This aligns broadcast sync_timeout with existing connection timeouts
which are 20 seconds long.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Stable-dep-of: b37cab58 ("Bluetooth: ISO: Don't reject BT_ISO_QOS if parameters are unset")
Signed-off-by: Sasha Levin <sashal@kernel.org>