x86: add led driver for PC Engines APU1

This driver adds the LED support for the PC Engines APU1.
This integrates the Linux kernel driver and includes a patch to support
 newer firmware versions. Also the default LED configuration is updated
 to use the correct devices.

Signed-off-by: Andreas Eberlein <foodeas@aeberlein.de>

target/linux/x86/base-files/lib/preinit/01_sysinfo

@@ -18,6 +18,10 @@ do_sysinfo_x86() {
 	for file in product_name board_name; do
 		product="$(cat /sys/devices/virtual/dmi/id/$file 2>/dev/null)"
 		case "$vendor:$product" in
+		"PC Engines:APU")
+			product="apu1"
+			break
+			;;
 		"Supermicro:Super Server")
 			continue
 			;;