package/directfb: drop bogus BR2_PACKAGE_DIRECTFB_CYBER5K

The inexistent symbol is reference since 2008, see commit '8a12bab608
widen options to configure directfb, patch by Micha Nelissen
<micha@neli.hopto.org>'

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/directfb/directfb.mk

@@ -67,7 +67,6 @@ endif
 
 DIRECTFB_GFX = \
 	$(if $(BR2_PACKAGE_DIRECTFB_ATI128),ati128) \
-	$(if $(BR2_PACKAGE_DIRECTFB_CYBER5K),cyber5k) \
 	$(if $(BR2_PACKAGE_DIRECTFB_MATROX),matrox) \
 	$(if $(BR2_PACKAGE_DIRECTFB_PXA3XX),pxa3xx) \
 	$(if $(BR2_PACKAGE_DIRECTFB_I830),i830) \