virtio-9p: Create a commandline option -fsdev

This patch creates a new command line option named -fsdev to hold any file
system specific information.

The option will currently hold the following attributes:
-fsdev fstype id=id,path=path_to_share
where
fstype: Type of the file system.
id:     Identifier used to refer to this fsdev
path:   The path on the host that is identified by this fsdev.

[aneesh.kumar@linux.vnet.ibm.com: Abstraction using FsContext]
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/file-op-9p.h

@@ -0,0 +1,32 @@
+/*
+ * Virtio 9p
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#ifndef _FILEOP_H
+#define _FILEOP_H
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/time.h>
+#include <utime.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+
+typedef struct FsContext
+{
+    char *fs_root;
+    uid_t uid;
+} FsContext;
+
+typedef struct FileOperations
+{
+    void *opaque;
+} FileOperations;
+#endif