[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.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 4fec28a..b564f18 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -54,6 +54,7 @@
 	SRP_PORT_REDIRECT	= 1,
 	SRP_DLID_REDIRECT	= 2,
 
+	SRP_MAX_LUN		= 512,
 	SRP_MAX_IU_LEN		= 256,
 
 	SRP_RQ_SHIFT    	= 6,