add #include <linux/fs_pin.h> for more modern kernels; check if this kernel version is appropriate

jbb_gpl/hook.c

@@ -89,6 +89,10 @@ driver_xxxx - Module specific functions such as open, close and ioctl.
 #include <asm/uaccess.h>  /* VERIFY_WRITE */
 #include <asm/io.h>
 
+# if ( LINUX_VERSION_CODE > KERNEL_VERSION(3,19,0) )
+#include <linux/fs_pin.h>
+#endif
+
 #include "jbb.h"
 
 MODULE_LICENSE("GPL");