Use -Werror in external/wpa_supplicant_8/hostapd

* Suppress existing warnings.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Ia610966bb1bb9baa32449aaecca1f586777f8479
diff --git a/hostapd/Android.mk b/hostapd/Android.mk
index 04060ab..bbc9c0b 100644
--- a/hostapd/Android.mk
+++ b/hostapd/Android.mk
@@ -24,9 +24,14 @@
 # Set Android log name
 L_CFLAGS += -DANDROID_LOG_NAME=\"hostapd\"
 
+L_CFLAGS += -Wall -Werror
+
 # Disable unused parameter warnings
 L_CFLAGS += -Wno-unused-parameter
 
+# Disable unused variable warnings
+L_CFLAGS += -Wno-unused-variable
+
 # Disable macro redefined warnings
 L_CFLAGS += -Wno-macro-redefined