headers_check fix: linux/nubus.h

fix the following 'make headers_check' warning:

  usr/include/linux/nubus.h:232: found __[us]{8,16,32,64} type without #include <linux/types.h>

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
diff --git a/include/linux/nubus.h b/include/linux/nubus.h
index c435507..7382af3 100644
--- a/include/linux/nubus.h
+++ b/include/linux/nubus.h
@@ -12,6 +12,7 @@
 #ifndef LINUX_NUBUS_H
 #define LINUX_NUBUS_H
 
+#include <linux/types.h>
 #ifdef __KERNEL__
 #include <asm/nubus.h>
 #endif