package/wpa_supplicant: Enable support for log to debug file

Enable the '-f' option (log output to debug file instead of stdout). Force
enable it, binary size +963 bytes for an ARM target.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/wpa_supplicant/wpa_supplicant.mk

@@ -23,7 +23,8 @@ WPA_SUPPLICANT_CONFIG_ENABLE = \
 	CONFIG_IEEE80211AC	\
 	CONFIG_IEEE80211N	\
 	CONFIG_IEEE80211R	\
-	CONFIG_INTERNAL_LIBTOMMATH
+	CONFIG_INTERNAL_LIBTOMMATH \
+	CONFIG_DEBUG_FILE
 
 WPA_SUPPLICANT_CONFIG_DISABLE = \
 	CONFIG_SMARTCARD