[FS#452] Mamba leds fix possibly wrong

[LEDE Bugs]

The following task is now closed:

FS#452 - Mamba leds fix possibly wrong
User who did this - Mathias Kresin (mkresin)

Reason for closing: Invalid report
Additional comments about closing: Please do not create tickets for possible bugs on devices you do not have. Contact the author instead. This commit was tested on all mvebu boards and the change is correct.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=452