wpa_supplicant: fix static build with EAP enabled

Disable EAP-TNC for static build because its implementation uses dlopen().

 Fixes:
http://autobuild.buildroot.net/results/e21/e21705ae690ab899b6f00e4a15833abef5e54e0e/

[Peter: add comment explaining why]
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/wpa_supplicant/wpa_supplicant.mk

@@ -45,6 +45,10 @@ endif
 # Trailing underscore on purpose to not enable CONFIG_EAPOL_TEST
 ifeq ($(BR2_PACKAGE_WPA_SUPPLICANT_EAP),y)
 WPA_SUPPLICANT_CONFIG_ENABLE += CONFIG_EAP_
+# uses dlopen()
+ifeq ($(BR2_STATIC_LIBS),y)
+WPA_SUPPLICANT_CONFIG_DISABLE += CONFIG_EAP_TNC
+endif
 else
 WPA_SUPPLICANT_CONFIG_DISABLE += CONFIG_EAP
 endif