scsi,rcu: Convert call_rcu(fc_rport_free_rcu) to kfree_rcu()

The rcu callback fc_rport_free_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(fc_rport_free_rcu).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>