[virtio-9p] This patch implements TLCREATE for 9p2000.L protocol.

[virtio-9p]  This patch implements TLCREATE for 9p2000.L protocol.

SYNOPSIS

    size[4] Tlcreate tag[2] fid[4] name[s] flags[4] mode[4] gid[4]

    size[4] Rlcreate tag[2] qid[13] iounit[4]

DESCRIPTION

The Tlreate request asks the file server to create a new regular file with the
name supplied, in the directory (dir) represented by fid.
The mode argument specifies the permissions to use. New file is created with
the uid if the fid and with supplied gid.

The flags argument represent Linux access mode flags with which the caller
is requesting to open the file with. Protocol allows all the Linux access
modes but it is upto the server to allow/disallow any of these acess modes.
If the server doesn't support any of the access mode, it is expected to
return error.

To start with we will not restricit/limit any Linux flags on this server.
If needed, We can start restricting as we move forward with various use cases.

Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>