Bluetooth: controller: Release resources on failed AUX_CONNECT_RSP

We allocate nodes on receiving AUX_CONNECT_REQ, but we can only use
them if AUX_CONNECT_RSP is sent successfully. If that fails, we need
to release those nodes.

Signed-off-by: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>