Allow wifi p2p to use legacy dedicated address

Some exsting applications may expect wifi p2p use legacy
"192.168.49.1/24" address. Have a configuration for wifi p2p to
decide whether to use legacy dedicated address or random address.

Bug: 161520826
Test: atest TetheringTests
Change-Id: If79973416a6780ee19ee785c65772b1a2dc1fbf7