wlan: Update set disable channel list command implementation

Currently driver disables channels received in
SET_DISABLE_CHANNEL_LIST command, only when sap
is turned on (on start bss). According to new requirement,
channels should be disabled as soon as the command is received.

To meet above expectation update the set disable channel list
command functionality to disable the channels as soon as the
command is received.

Change-Id: I596c21847e90efef9676f20df528aed77e927519
CRs-fixed: 2413505