ramips: add missing LEDs to Asus RT-AX53U

This patch adds the missing LEDs to Asus RT-AX53U.
Based on PR #10400 and patch provided in #11068
 - enable the two LEDs controlled by mt7915e for wireless;
 - add label to power LED so it works properly and fix formatting;
 - add the USB LED;
 - switch LEDs are best left to be controlled by hardware for now.

Co-Authored-By: Ivan Rozhuk <rozhuk.im@gmail.com>
Co-Authored-By: Shiji Yang <yangshiji66@qq.com>
Co-Authored-By: Hartmut Birr <e9hack@gmail.com>
Tested-by: Felix Baumann <felix.bau@gmx.de>
Tested-by: Marian Sarcinschi <znevna@gmail.com>
Signed-off-by: Marian Sarcinschi <znevna@gmail.com>