libxml2: remove unused BR2_PACKAGE_LIBXML2_TARGET_HEADERS option

package/libxml2/Config.in

@@ -3,11 +3,3 @@ config BR2_PACKAGE_LIBXML2
 	help
 	  XML C Parser
 	  ftp://xmlsoft.org/libxml2
-
-config BR2_PACKAGE_LIBXML2_TARGET_HEADERS
-	bool "libxml2 target headers"
-	depends on BR2_PACKAGE_LIBXML2
-	help
-	  XML C Parser
-	  ftp://xmlsoft.org/libxml2
-