P2P: Add support for IP address assignment in 4-way handshake

P2P: Add support for IP address assignment in 4-way handshake

This new mechanism allows P2P Client to request an IPv4 address from the
GO as part of the 4-way handshake to avoid use of DHCP exchange after
4-way handshake. If the new mechanism is used, the assigned IP address
is shown in the P2P-GROUP-STARTED event on the client side with
following new parameters: ip_addr, ip_mask, go_ip_addr. The assigned IP
address is included in the AP-STA-CONNECTED event on the GO side as a
new ip_addr parameter. The IP address is valid for the duration of the
association.

The IP address pool for this new mechanism is configured as global
wpa_supplicant configuration file parameters ip_addr_go, ip_addr_mask,
ip_addr_star, ip_addr_end. For example:

ip_addr_go=192.168.42.1
ip_addr_mask=255.255.255.0
ip_addr_start=192.168.42.2
ip_addr_end=192.168.42.100

DHCP mechanism is expected to be enabled at the same time to support P2P
Devices that do not use the new mechanism. The easiest way of managing
the IP addresses is by splitting the IP address range into two parts and
assign a separate range for wpa_supplicant and DHCP server.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>