mlx4_core: Get the maximum message size from reported device capabilities

Get the maximum message size from the device capabilities returned
from the QUERY_DEV_CAP firmware command, rather than hard-coding 2 GB.

Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/net/mlx4/fw.h b/drivers/net/mlx4/fw.h
index 296254a..7e1dd9e 100644
--- a/drivers/net/mlx4/fw.h
+++ b/drivers/net/mlx4/fw.h
@@ -60,6 +60,7 @@
 	int max_rdma_global;
 	int local_ca_ack_delay;
 	int num_ports;
+	u32 max_msg_sz;
 	int max_mtu[MLX4_MAX_PORTS + 1];
 	int max_port_width[MLX4_MAX_PORTS + 1];
 	int max_vl[MLX4_MAX_PORTS + 1];