wlan: Delete p2p interface while SAP mode

A recent fix I13c7d5230a65d2fb66099de52b79f19ec4072135,
deletes p2p interface that is created during
init. In case of SAP mode, this is causing the total number
of connections to reduce by 1 and thus affects some test
scenarios.

Remove the p2p interface while SAP mode and then restore the same when
SAP exits.

Change-Id: I6a5df12e8beec9237f8db19d675d40a17abc3d7c