[IB] srp: increase max_luns

Increase SRP max_luns to 512 to match the kernel's default, since SRP
storage targets can have lots of LUNs and the SRP initiator itself
doesn't have any particular limit.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 321a3a1..a364530 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1417,6 +1417,8 @@
 	if (!target_host)
 		return -ENOMEM;
 
+	target_host->max_lun = SRP_MAX_LUN;
+
 	target = host_to_target(target_host);
 	memset(target, 0, sizeof *target);