P2P: Fix p2p_scan() error processing in p2p_search()

P2P: Fix p2p_scan() error processing in p2p_search()

Commit 39185dfa549f076a6be114e0149a3649d302f477 changed the p2p_scan()
callback to return 1 in some cases, but forgot to change this p2p_scan()
call to handle that properly. Fix this by processing any non-zero value
as an error. This regression could leave the P2P module in state where
it believed a P2P scan was still running and refused to start some
operations until that scan gets completed (which would never happen
since it was not really started).

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>