NTB: Increase transport MTU to 64k from 16k

Benchmarking showed a significant performance increase with the MTU size
to 64k instead of 16k.  Change the driver default to 64k.
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

drivers/ntb/ntb_transport.c

@@ -76,7 +76,7 @@ static unsigned long max_mw_size;
 module_param(max_mw_size, ulong, 0644);
 MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
 
-static unsigned int transport_mtu = 0x401E;
+static unsigned int transport_mtu = 0x10000;
 module_param(transport_mtu, uint, 0644);
 MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");