staging: lustre: ptlrpc: include ptlrpc_internal.h

Remove sparse warning "symbol 'sptlrpc_plain_init' was not declared"
by including ptlrpc_internal.h, which includes sptlrpc_plain_init.

Signed-off-by: Anders Fridlund <anders.fridlund@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ptlrpc/sec_plain.c

@@ -46,6 +46,7 @@
 #include "../include/obd_class.h"
 #include "../include/lustre_net.h"
 #include "../include/lustre_sec.h"
+#include "ptlrpc_internal.h"
 
 struct plain_sec {
 	struct ptlrpc_sec       pls_base;