Remove WIFI_ENABLE.

The WIFI_ENABLE is currently set by buildroot makefile. To be
consistent, remove it from the local makefile.

Change-Id: I864e10355801052af16b3c4c35b5dd89abaab662
diff --git a/Makefile b/Makefile
index 7d583e0..9afb254 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@
 pfe_ctrl/install: fci/install
 
 pfe_ctrl/all:
-	$(MAKE) -C pfe_ctrl $(LINUX_MAKE_FLAGS) KERNELDIR=$(LINUX_DIR) PFE_DIR=../pfe WIFI_ENABLE=y
+	$(MAKE) -C pfe_ctrl $(LINUX_MAKE_FLAGS) KERNELDIR=$(LINUX_DIR) PFE_DIR=../pfe
 
 pfe_ctrl/install:
 	$(MAKE) -C $(LINUX_DIR) $(LINUX_MAKE_FLAGS) M="$(shell /bin/pwd)/pfe_ctrl" modules_install