fsdev: spelling fix

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/fsdev/virtfs-proxy-helper.texi b/fsdev/virtfs-proxy-helper.texi
index 6eb2d50..f4cbb60 100644
--- a/fsdev/virtfs-proxy-helper.texi
+++ b/fsdev/virtfs-proxy-helper.texi
@@ -15,7 +15,7 @@
 
 2) Running QEMU with root privilege could be a security issue.
 
-To overcome above issues, following approach is used: A new filesytem
+To overcome above issues, following approach is used: A new filesystem
 type 'proxy' is introduced. Proxy FS uses chroot + socket combination
 for securing the vulnerability known with following symbolic links.
 Intention of adding a new filesystem type is to allow qemu to run