drivers/net/wireless/ath/wil6210: Makefile, only -Werror when no -W* in EXTRA_CFLAGS

  When make with EXTRA_CFLAGS=-W, it will report error.
  so give a check in Makefile.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Acked-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/wil6210/Makefile

@@ -9,5 +9,7 @@ wil6210-objs += wmi.o
 wil6210-objs += interrupt.o
 wil6210-objs += txrx.o
 
-subdir-ccflags-y += -Werror
+ifeq (, $(findstring -W,$(EXTRA_CFLAGS)))
+	subdir-ccflags-y += -Werror
+endif
 subdir-ccflags-y += -D__CHECK_ENDIAN__