add NanoPi R76S support for edge kernel builds (#8609)

Author: SuperKali

config/boards/nanopi-r76s.conf

@@ -2,7 +2,7 @@
 BOARD_NAME="NanoPi R76S"
 BOARDFAMILY="rk35xx"
 BOOTCONFIG="nanopi-r76s-rk3576_defconfig"
-KERNEL_TARGET="vendor" # WIP: current & edge kernel
+KERNEL_TARGET="vendor,edge" # WIP: current kernel
 FULL_DESKTOP="yes"
 BOOT_LOGO="desktop"
 BOOT_FDT_FILE="rockchip/rk3576-nanopi-r76s.dtb"