package/libopenvg: convert to the virtual-package infrastructure

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Eric Le Bihan <eric.le.bihan.dev@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Cc: Mike Zick <minimod@morethan.org>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/opengl/libopenvg/libopenvg.mk

@@ -4,13 +4,4 @@
 #
 ################################################################################
 
-LIBOPENVG_SOURCE =
-LIBOPENVG_DEPENDENCIES = $(call qstrip,$(BR2_PACKAGE_PROVIDES_LIBOPENVG))
-
-ifeq ($(BR2_PACKAGE_HAS_LIBOPENVG),y)
-ifeq ($(LIBOPENVG_DEPENDENCIES),)
-$(error No libOpenVG implementation selected. Configuration error.)
-endif
-endif
-
-$(eval $(generic-package))
+$(eval $(virtual-package))