volatile-binds: mount-copybind: fix typo

Amend a small typing error.

(From OE-Core rev: 6d3c24cfc269fbcd49acd8be220395500fc7120c)

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/volatile-binds/files/mount-copybind

@@ -49,7 +49,7 @@ if [ -d "$mountpoint" ]; then
         mkdir "${overlay_workdir}"
     fi
 
-    # Try to mount using overlay, which is must faster than copying files.
+    # Try to mount using overlay, which is much faster than copying files.
     # If that fails, fall back to slower copy.
     if command -v selinuxenabled > /dev/null 2>&1; then
         if selinuxenabled; then