[][MAC80211][hostapd][Revert set_send_disassoc_frame_timer]

[Description]
Remove the function set_send_disassoc_frame_timer(). Originally, this
function was added for MBO TC 4.2.5.3 to fix missing disassociate frame
in connac2 chip. While the issue can not be reproduced on both connac2
and connac3 chip, we shall remove this function.

[Release-log]
N/A

Change-Id: I2e35f42ab196aac7a564a860f6d403b405655f9f
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7822626
2 files changed