staging: rtl8723bs: core: rtw_mlme_ext.c: remove deadcode

'CHECK_EVENT_SEQ' is not defined anywhere, remove the deadcode.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20210531140234.3352465-1-yukuai3@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>