[WCNCR00146538] softap: Add command for listing channel dirtiness

[Description]
Add command for listing channel dirtiness.

Command: iwpriv wlan0 driver "GET_CH_DIRTINESS"

Result:
    wlan0     driver:
    ch 136 -> dirtiness 0
    ch 124 -> dirtiness 0
    ...
    ch 005 -> dirtiness 1017
    ch 008 -> dirtiness 1085
    ch 007 -> dirtiness 1134
    ch 010 -> dirtiness 1176

Change-Id: I90cf7a66027ad3bc7cb716944cab02e7ca10259c
Signed-off-by: Awk Jiang <awk.jiang@mediatek.com>
CR-Id: WCNCR00146538
Feature: softap
1 file changed