verbs: Set default MTU for the xsrq ping-pong to be 1024

According to Annex 16 (RoCE), the Rate and MTU values are obtained using
Ethernet management practices. The default MTU for the Ethernet is 1500,
so let's change the default MTU for ibv_xsrq_pingpong to be consistent
with Ethernet practices.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>

libibverbs/examples/xsrq_pingpong.c

@@ -825,7 +825,7 @@ static void init(void)
 	ctx.ib_port = 1;
 	ctx.num_clients  = 1;
 	ctx.num_tests = 5;
-	ctx.mtu = IBV_MTU_2048;
+	ctx.mtu = IBV_MTU_1024;
 	ctx.sl = 0;
 	ctx.gidx = -1;
 }