Don't include <linux/...> header files directly.

These change from kernel release to release, and no longer contain some of
the stuff you need.

Change-Id: I3fc7176cf2246aebfc0aa2a833dfa04ea8d931fc
diff --git a/ResolverController.cpp b/ResolverController.cpp
index 680be20..23554e8 100644
--- a/ResolverController.cpp
+++ b/ResolverController.cpp
@@ -19,7 +19,7 @@
 
 #include <cutils/log.h>
 
-#include <linux/if.h>
+#include <net/if.h>
 
 // NOTE: <resolv_iface.h> is a private C library header that provides
 //       declarations for _resolv_set_default_iface() and others.