dix: let change_modmap() return BadValue instead of -1

The function returns X result codes, but -1 isn't a valid value here.
Therefore all callers explicitly translate -1 to BadValue, so we can return
that directly instead of -1.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

Xi/setmmap.c

@@ -103,15 +103,10 @@ ProcXSetDeviceModifierMapping(ClientPtr client)
         rep.success = ret;
         WriteReplyToClient(client, sizeof(xSetDeviceModifierMappingReply),
                            &rep);
-    }
-    else if (ret == -1) {
-        return BadValue;
-    }
-    else {
-        return ret;
+        return Success;
     }
 
-    return Success;
+    return ret;
 }
 
 /***********************************************************************

dix/devices.c

@@ -1771,7 +1771,7 @@ ProcSetModifierMapping(ClientPtr client)
 
     rc = change_modmap(client, PickKeyboard(client), (KeyCode *) &stuff[1],
                        stuff->numKeyPerModifier);
-    if (rc == MappingFailed || rc == -1)
+    if (rc == MappingFailed)
         return BadValue;
     if (rc != MappingSuccess && rc != MappingFailed && rc != MappingBusy)
         return rc;

dix/inpututils.c

@@ -150,7 +150,7 @@ check_modmap_change(ClientPtr client, DeviceIntPtr dev, KeyCode *modmap)
          * keycode range. */
         if (i < xkb->min_key_code || i > xkb->max_key_code) {
             client->errorValue = i;
-            return -1;
+            return BadValue;
         }
 
         /* None of the new modifiers may be down while we change the