ramips: add missing LEDs to Asus RT-AX53U

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 <[email protected]>
Co-Authored-By: Shiji Yang <[email protected]>
Co-Authored-By: Hartmut Birr <[email protected]>
Tested-by: Felix Baumann <[email protected]>
Tested-by: Marian Sarcinschi <[email protected]>
Signed-off-by: Marian Sarcinschi <[email protected]>
(cherry picked from commit c4b806d5c4ccc653968620e6e9aec93bc4e370e5)