rtlwifi: remove dummy hal_op rx_command_packet from rtl8188ee and rtl8723ae

The caller of hal_op rx_command_packet will assert function pointer
before calling, so we can remove dummy functions safely.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>