nl80211: Fix regression in P2P group interface removal

nl80211: Fix regression in P2P group interface removal

Commit 390e489c0d9415caf103367136eaa534b559837c extended hostapd BSS
interface removal capabilities. However, it ended up causing a
regression in wpa_supplicant P2P group interface handling. That P2P
group interface is removed through another driver_nl80211.c BSS context
and as such, the bss->added_if is not set. Fix this by verifying whether
the request is for another ifindex and if so, removing the interface
even if added_if is not marked.

Signed-hostap: Jouni Malinen <j@w1.fi>