package/x11r7/xdriver_xf86-video-ati: fix glamor dependency

Glamor support needs egl, fix dependency after
https://git.buildroot.net/buildroot/commit/?id=5b4bcbdafbe8e7b42d4e085a0524d70665cdbaf5

Fixes
http://autobuild.buildroot.net/results/6ac/6acd5ad820a47fc3442d3e3a5d8d72b396fb6e41/



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>