Map evdev keycode KEY_FAVORITES to XF86Favorites

NB: The value of KEY_FAVORITES is 0x16c (364) and thus beyond 255,
which is not supported by X11. It might also need a recent xkbcomp
that is patched so it does not throw fatal errors for those. See
https://lists.x.org/archives/xorg-devel/2017-April/053389.html

https://bugs.freedesktop.org/show_bug.cgi?id=100709



Signed-off-by: Christian Kellner <christian@kellner.me>