ntb_pingpong: Fix db_init parameter description

Fix 'db_init' parameter description.
Signed-off-by: NWei Yongjun <weiyj.lk@gmail.com>
Acked-by: NAllen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

drivers/ntb/test/ntb_pingpong.c

@@ -88,7 +88,7 @@ MODULE_PARM_DESC(delay_ms, "Milliseconds to delay the response to peer");
 
 static unsigned long db_init = 0x7;
 module_param(db_init, ulong, 0644);
-MODULE_PARM_DESC(delay_ms, "Initial doorbell bits to ring on the peer");
+MODULE_PARM_DESC(db_init, "Initial doorbell bits to ring on the peer");
 
 struct pp_ctx {
 	struct ntb_dev			*ntb;