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>
diff --git a/qemu-config.c b/qemu-config.c
index 9f0f143..cda5060 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -151,6 +151,24 @@
     },
 };
 
+#ifdef CONFIG_LINUX
+QemuOptsList qemu_fsdev_opts = {
+    .name = "fsdev",
+    .implied_opt_name = "fstype",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_fsdev_opts.head),
+    .desc = {
+        {
+            .name = "fstype",
+            .type = QEMU_OPT_STRING,
+        }, {
+            .name = "path",
+            .type = QEMU_OPT_STRING,
+        },
+        { /*End of list */ }
+    },
+};
+#endif
+
 QemuOptsList qemu_device_opts = {
     .name = "device",
     .implied_opt_name = "driver",