rtlwifi: rtl8821ae: Remove set but not used variables 'cur_txokcnt' and 'b_last_is_cur_rdl_state'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/wireless/realtek/rtlwifi/rtl8821ae/dm.c: In function rtl8821ae_dm_check_rssi_monitor:
drivers/net/wireless/realtek/rtlwifi/rtl8821ae/dm.c:658:6: warning: variable cur_txokcnt set but not used [-Wunused-but-set-variable]
drivers/net/wireless/realtek/rtlwifi/rtl8821ae/dm.c: In function rtl8821ae_dm_check_edca_turbo:
drivers/net/wireless/realtek/rtlwifi/rtl8821ae/dm.c:2657:7: warning: variable b_last_is_cur_rdl_state set but not used [-Wunused-but-set-variable]

They are never used so can be removed.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>