ath10k: fix IBSS scanning on wmi-tlv and qca6174

WLAN.RM.2.0-00073 firmware requires self-peer to
be created prior to issuing scan command. Without
this wmi-tlv with qca6174 firmware crashes after
submitting a scan request.

Creating the peer as soon as add_interface()
shouldn't be a problem.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>