package/x11r7/xserver_xorg-server: remove optional support for tslib

Upstream removed support for tslib:
https://cgit.freedesktop.org/xorg/xserver/commit/configure.ac?h=server-1.20-branch&id=5c7ed785e3bdb9f0fbf8fbfdc93b5fdd2b2c7dbf

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 974448aed3e54b048aa527482cfa935bbe0daeae)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/x11r7/xserver_xorg-server/xserver_xorg-server.mk

@@ -106,11 +106,6 @@ XSERVER_XORG_SERVER_CONF_OPTS += --disable-dri --disable-glx
 endif
 
 # Optional packages
-ifeq ($(BR2_PACKAGE_TSLIB),y)
-XSERVER_XORG_SERVER_DEPENDENCIES += tslib
-XSERVER_XORG_SERVER_CONF_OPTS += --enable-tslib LDFLAGS="-lts"
-endif
-
 ifeq ($(BR2_PACKAGE_HAS_UDEV),y)
 XSERVER_XORG_SERVER_DEPENDENCIES += udev
 XSERVER_XORG_SERVER_CONF_OPTS += --enable-config-udev