hostapd(hidl): Add HIDL interface skeletal code

Adding support for HIDL IPC in hostapd. This CL only adds the skeletal
framework for supporting HIDL interface implementation.

There is also a change in the hostapd.h to fix a C++ compilation error.

Bug: 36646171
Test: Compiles with CONFIG_CTRL_IFACE_HIDL=y in android.config
Change-Id: I4a7047a56f8e9be1ed51f2315df707ef5daddc11
diff --git a/hostapd/hostapd.android.rc b/hostapd/hostapd.android.rc
index 36b00af..85c63d0 100644
--- a/hostapd/hostapd.android.rc
+++ b/hostapd/hostapd.android.rc
@@ -7,13 +7,12 @@
 #
 
 on post-fs-data
-    mkdir /data/misc/wifi/hostapd 0770 wifi wifi
+    mkdir /data/vendor/wifi 0770 wifi wifi
+    mkdir /data/vendor/wifi/hostapd 0770 wifi wifi
 
-service hostapd /vendor/bin/hostapd \
-        /data/misc/wifi/hostapd.conf
+service hostapd /vendor/bin/hw/hostapd
     class main
     user wifi
     group wifi net_raw net_admin
-    writepid /data/misc/wifi/hostapd.pid
     disabled
     oneshot