NFS: Display the "fsc=" mount option if it is set

With this patch, mount command will show fsc=xxx if set:

If -o fsc=6666
clientaddr=192.168.122.208,fsc=6666,local_lock=none

If only -o fsc
clientaddr=192.168.122.208,fsc,local_lock=none

Signed-off-by: Chen Hanxiao <chenhx.fnst@fujitsu.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>