[IPV4] MROUTE: Adjust include files for user-space.

<linux/mroute.h> needs <linux/types.h>.
Avoid including <linux/in.h> in user-space, which conflicts with
standard <netinet/in.h>.
Add basic struct and constant in <linux/pim.h>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/include/linux/mroute.h b/include/linux/mroute.h
index c41b421..de4decf 100644
--- a/include/linux/mroute.h
+++ b/include/linux/mroute.h
@@ -2,7 +2,10 @@
 #define __LINUX_MROUTE_H
 
 #include <linux/sockios.h>
+#include <linux/types.h>
+#ifdef __KERNEL__
 #include <linux/in.h>
+#endif
 #include <linux/pim.h>
 
 /*