ath10k: allocate fw resources for iface combinations

The number of 3 vdevs wasn't enough to handle the
worst case for interface combinations in practice.

wpa_supplicant may need up to 4 vifs to have 2
vifs actually connected, i.e. p2pdev + client + 2x
p2p (either p2p client or p2p go).

This fixes worst case warning:

  Free vdev map is empty, no more interfaces allowed.

This keeps the ability to associate 32 stations in
AP mode at the cost of not being able to guarantee
that under all circumstances, i.e. some
combinations may consume additional fw peer
entries for internal purposes leaving less
resource for stations in AP mode.

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