driver_wext: declare wext private lib functions up front for build to succeed

Change-Id: I6d6c7d5153738b0ddd4d217a513397987eeb7434
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
diff --git a/src/drivers/driver_wext.c b/src/drivers/driver_wext.c
index 4f22242..62c1832 100644
--- a/src/drivers/driver_wext.c
+++ b/src/drivers/driver_wext.c
@@ -33,6 +33,8 @@
 
 #ifdef ANDROID
 #include "android_drv.h"
+int wpa_driver_wext_driver_cmd( void *priv, char *cmd, char *buf, size_t buf_len );
+int wpa_driver_signal_poll(void *priv, struct wpa_signal_info *si);
 #endif /* ANDROID */
 
 static int wpa_driver_wext_flush_pmkid(void *priv);