wpa_supplicant(hidl): Create a version subfolder

This is needed to support multiple HIDL interface version
implementations simultaneously in the tree.

The makefile variable |HIDL_INTERFACE_VERSION| will be used to chose
between the 2:
On oc-dev branch, HIDL_INTERFACE_VERSION := 1.0
On master branch, HIDL_INTERFACE_VERSION := 1.1

Bug: 38349675
Test: Compiles
Change-Id: I73c346f0d5da140295f9c880c35b79c14da206f0
diff --git a/wpa_supplicant/notify.c b/wpa_supplicant/notify.c
index c720c32..9464c4b 100644
--- a/wpa_supplicant/notify.c
+++ b/wpa_supplicant/notify.c
@@ -23,7 +23,7 @@
 #include "p2p_supplicant.h"
 #include "sme.h"
 #include "notify.h"
-#include "hidl/hidl.h"
+#include "hidl.h"
 
 int wpas_notify_supplicant_initialized(struct wpa_global *global)
 {