wifi: rtlwifi: cleanup struct rtl_ps_ctl

Remove set but otherwise unused 'sleep_ms', 'last_action', 'state'
and 'last_slept' members of 'struct rtl_ps_ctl' (these seems to be
a leftovers from some older code) and adjust 'rtl_swlps_wq_callback()'
accordingly. Compile tested only.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231013124534.19714-1-dmantipov@yandex.ru