[mutter] backends/x11: Fix c&p issue in tablet area calculation

[Carlos Garnacho <carlosg src gnome org>]

commit 48e820235ea8129c232695874a3336a448f71450
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Jun 16 18:02:50 2017 +0200

    backends/x11: Fix c&p issue in tablet area calculation
    
    instead of filling in the last array value, it overwrote the previous one.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=781703

 src/backends/x11/meta-input-settings-x11.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/backends/x11/meta-input-settings-x11.c b/src/backends/x11/meta-input-settings-x11.c
index 174fd32..e111ceb 100644
--- a/src/backends/x11/meta-input-settings-x11.c
+++ b/src/backends/x11/meta-input-settings-x11.c
@@ -609,7 +609,7 @@ meta_input_settings_x11_set_tablet_area (MetaInputSettings  *settings,
   area[0] = width * padding_left;
   area[1] = height * padding_top;
   area[2] = width - (width * padding_right);
-  area[2] = height - (height * padding_bottom);
+  area[3] = height - (height * padding_bottom);
   update_tablet_area (settings, device, area);
 }