Allow user mode NFS server to run without rpcbind / portmap

Allow user mode NFS server to run without rpcbind / portmap

and nfsroot mount without the need to talk to an RPC info
server as long as the port numbers for mountd and nfsd
are known in advance.

This patch updates the qemu startup scripts and the
user mode NFS server to have the ability to start
without the need to use rpcbind or portmap services.

(From OE-Core rev: 3b1346c607c41a2d592c48594457c32153cb2314)

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>