wpa-supplicant: add 802.11r client support

Add 802.11r client support to wpa_supplicant. It's only enabled in
wpa_supplicant-full. hostapd gained 802.11r support in commit r45051.

Tested on a TP-Link TL-WR710N sta psk client with two 802.11r enabled
openwrt accesspoints (TP-Link TL-WDR3600).

Signed-off-by: Stefan Hellermann <stefan@the2masters.de>

SVN-Revision: 46377