treewide: use only board_name function to get name

Do not parse /tmp/sysinfo/board_name, /proc/cpuinfo or the device tree
compatible string directly. Always use the board_name function to get
the board name.

The admswconfig package still reads /proc/cpuinfo directly. The code
looks somehow broken and the whole adm5120 which uses this package
looks unmaintained. Leave it as it is for now.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/orion/base-files/etc/hotplug.d/usb/10-usb

@@ -30,9 +30,9 @@ usb_led_off() {
 }
 
 get_usb_led() {
-	local hardware=`sed -n /Hardware/s/.*:.//p /proc/cpuinfo`
+	. /lib/functions.sh
 
-	case "${hardware}" in
+	case "$(board_name)" in
 	 'Linksys WRT350N v2')
 		usb_led='wrt350nv2:green:usb'
 		usb_device='1-1:1.0'