NTB: ntb_transport: Fix too small buffer for debugfs_name

The buffer used for "qp%d" was only 4 bytes, which truncates names like
"qp10" to "qp1" and causes multiple queues to share the same directory.

Enlarge the buffer and use sizeof() to avoid truncation.

Fixes: fce8a7b ("PCI-Express Non-Transparent Bridge Support")
Cc: <stable@vger.kernel.org> # v3.9+
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

Author: Koichiro Den

drivers/ntb/ntb_transport.c

@@ -1252,9 +1252,9 @@ static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 	qp->tx_max_entry = tx_size / qp->tx_max_frame;
 
 	if (nt->debugfs_node_dir) {
-		char debugfs_name[4];
+		char debugfs_name[8];
 
-		snprintf(debugfs_name, 4, "qp%d", qp_num);
+		snprintf(debugfs_name, sizeof(debugfs_name), "qp%d", qp_num);
 		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
 						     nt->debugfs_node_dir);