Handle survey event properly in wpa_supplicant

Handle survey event properly in wpa_supplicant

Let's reuse hostapd code for such handling. This will be useful to get
ACS support into wpa_supplicant where this one needs to handle the
survey event so it fills in the result ACS subsystem will require.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
[u.oelmann@pengutronix.de: rebased series from hostap_2_1~944 to master]
Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>