BugLink: https://launchpad.net/bugs/1512999

For Edge Gateway 5000/5100 only.

Add code for controlling bluetooth LED via firmware, and turns
the LED on and off when the interface is up and down accordingly.

Base on the code found at
https://chromium.googlesource.com/chromiumos/third_party/kernel/+/8300e2ccad47c5c2f10507661c10d4892211790e%5E%21/#F0Signed-off-by: Wen-chien Jesse Sung <jesse.sung@canonical.com>
Reviewed-By: AceLan Kao <acelan.kao@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>