linux-xlnx.inc: Fixing machine override for KERNEL_FEATURES
Using a += with machine override will overwrite later append statements.
Changing to '_append' to fix this behavior.
@@ -42,4 +42,4 @@ SRC_URI_append = " file://xilinx-kmeta;type=kmeta;name=xilinx-kmeta;destsuffix=x
# MicroBlaze BSP fragments
KERNEL_FEATURES_append_kc705-microblazeel = " bsp/kc705-microblazeel/kc705-microblazeel.scc"
-KERNEL_FEATURES_zynqmp += "${@bb.utils.contains('DISTRO_FEATURES', 'xen', ' bsp/xilinx/xen.scc', '', d)}"
+KERNEL_FEATURES_append_zynqmp = "${@bb.utils.contains('DISTRO_FEATURES', 'xen', ' bsp/xilinx/xen.scc', '', d)}"
