mac80211_hwsim: set p2p device interface support indication

P2P device interface type was not indicated in the supported
interface types even when hwsim was configured with p2p device
support. Fix it.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>