For P2P interfaces, some drivers (CC6UL) create auxiliar interfaces based
on the parent one, like p2p-p2p0-0.
This commit adds a p2p* pattern to the list of unmanaged devices so that
NetworkManager doesn't try to manage P2P devices.
https://jira.digi.com/browse/DEL-4649
Signed-off-by: Isaac Hermida <isaac.hermida@digi.com>