rtlwifi: rtl8192cu: mac: Fix some missing/ill-documented function parameters

Fixes the following W=1 kernel build warning(s):

 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c:124: warning: Function parameter or member 'hw' not described in 'rtl92c_llt_write'
 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c:124: warning: Excess function parameter 'io' description in 'rtl92c_llt_write'
 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c:155: warning: Function parameter or member 'hw' not described in 'rtl92c_init_llt_table'
 drivers/net/wireless/realtek/rtlwifi/rtl8192cu/mac.c:155: warning: Excess function parameter 'io' description in 'rtl92c_init_llt_table'

Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201102112410.1049272-4-lee.jones@linaro.org