wifi: Disallow iface creation based on mode

Based on the mode configured, limit the iface creation.

Note: Support for iface removal will be added in a follow up CL which
should help us use P2P or NAN iface dynamically.

Bug: 31997422
Test: Compiles
Change-Id: Idde2f3b749264d542d5d6608b0b2c5aa8103ade6