desktop-shell: fix a typo

Signed-off-by: Abdur Rehman <arehmanq199@gmail.com>
Reviewed-by: Yong Bakos <ybakos@humanoriented.com>
diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
index 3913f95..8388dc3 100644
--- a/desktop-shell/shell.c
+++ b/desktop-shell/shell.c
@@ -1911,7 +1911,7 @@
 		weston_desktop_surface_get_surface(shsurf->desktop_surface);
 
 	/* get the default output, if the client set it as NULL
-	   check whether the ouput is available */
+	   check whether the output is available */
 	if (output)
 		shsurf->output = output;
 	else if (es->output)