package/gtkiostream: drop optional dependency on libgtk2

As we're about to remove libgtk2, let's drop the optional dependency
of gtkiostream on libgtk2.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>

package/gtkiostream/gtkiostream.mk

@@ -39,10 +39,6 @@ ifeq ($(BR2_PACKAGE_LIBGLIB2),y)
 GTKIOSTREAM_DEPENDENCIES += libglib2
 endif
 
-ifeq ($(BR2_PACKAGE_LIBGTK2),y)
-GTKIOSTREAM_DEPENDENCIES += libgtk2
-endif
-
 ifeq ($(BR2_PACKAGE_LIBGTK3),y)
 GTKIOSTREAM_DEPENDENCIES += libgtk3
 endif