Suppress unused-parameter warnings.

external/wpa_supplicant_8 also suppress these warnings.
We should also do it here too.

Test: make -j lib_driver_cmd_simulated
Change-Id: I3e313ca7eb06966550800c9121902bc2ae1328bb
diff --git a/wifi/wpa_supplicant_8_lib/Android.mk b/wifi/wpa_supplicant_8_lib/Android.mk
index 8fee01d..d6ee953 100644
--- a/wifi/wpa_supplicant_8_lib/Android.mk
+++ b/wifi/wpa_supplicant_8_lib/Android.mk
@@ -58,6 +58,8 @@
 L_CFLAGS += -DCONFIG_ANDROID_LOG
 endif
 
+L_CFLAGS += -Wno-unused-parameter
+
 ########################
 
 include $(CLEAR_VARS)