SystemServer: cherry-pick p2p service start

Cherry-pick change that only starts P2P service if p2p is supported for
the device.

Disable WiFi p2p service if it's not supported.

b/26877020

Bug:34193861
Test: frameworks/base/wifi/tests/runtests.sh
Test: frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Test: manually verified wifi connection
Test: manually checked for p2p peers

Change-Id: I84b822fa57423711de75d2147effe73a1fc40eb4
Merged-In: I84b822fa57423711de75d2147effe73a1fc40eb4