package/sdl2: drop tslib

non existing tslib support has been dropped since version 2.0.14 and
https://github.com/libsdl-org/SDL/commit/4c96faee578efcba3f2d6afe8e2122f26b1dfb0b

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 083cd205c7e9f32145f7752502df7a2c24b519f2)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/sdl2/sdl2.mk

@@ -142,13 +142,6 @@ else
 SDL2_CONF_OPTS += --disable-video-opengles
 endif
 
-ifeq ($(BR2_PACKAGE_TSLIB),y)
-SDL2_DEPENDENCIES += tslib
-SDL2_CONF_OPTS += --enable-input-tslib
-else
-SDL2_CONF_OPTS += --disable-input-tslib
-endif
-
 ifeq ($(BR2_PACKAGE_ALSA_LIB),y)
 SDL2_DEPENDENCIES += alsa-lib
 SDL2_CONF_OPTS += --enable-alsa