rsi: Fix misnamed function parameter 'rx_pkt'

rsi: Fix misnamed function parameter 'rx_pkt'

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

 drivers/net/wireless/rsi/rsi_91x_main.c:157: warning: Function parameter or member 'rx_pkt' not described in 'rsi_read_pkt'
 drivers/net/wireless/rsi/rsi_91x_main.c:157: warning: Excess function parameter 'rcv_pkt' description in 'rsi_read_pkt'

Cc: Amitkumar Karwar <amitkarwar@gmail.com>
Cc: Siva Rebbagondla <siva8118@gmail.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
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/20200819072402.3085022-18-lee.jones@linaro.org