sunrpc: fix kernel-doc warnings

sunrpc: fix kernel-doc warnings

Fix kernel-doc warnings in sunrpc/rpc_pipe.c and
sunrpc/rpcb_clnt.c:

Warning(net/sunrpc/rpcb_clnt.c:428): No description found for parameter 'net'
Warning(net/sunrpc/rpcb_clnt.c:567): No description found for parameter 'net'

Warning(net/sunrpc/rpc_pipe.c:133): No description found for parameter 'pipe'
Warning(net/sunrpc/rpc_pipe.c:133): Excess function parameter 'inode' description in 'rpc_queue_upcall'
Warning(net/sunrpc/rpc_pipe.c:839): No description found for parameter 'pipe'
Warning(net/sunrpc/rpc_pipe.c:839): Excess function parameter 'ops' description in 'rpc_mkpipe_dentry'
Warning(net/sunrpc/rpc_pipe.c:839): Excess function parameter 'flags' description in 'rpc_mkpipe_dentry'
Warning(net/sunrpc/rpc_pipe.c:949): No description found for parameter 'dentry'
Warning(net/sunrpc/rpc_pipe.c:949): Excess function parameter 'clnt' description in 'rpc_remove_client_dir'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>