headers_check fix: linux/if_strip.h

fix the following 'make headers_check' warning:

  usr/include/linux/if_strip.h:22: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>

include/linux/if_strip.h

@@ -18,6 +18,8 @@
 #ifndef __LINUX_STRIP_H
 #define __LINUX_STRIP_H
 
+#include <linux/types.h>
+
 typedef struct {
     __u8 c[6];
 } MetricomAddress;