rsi: rsi_91x_sdio: Fix a few kernel-doc related issues

- File headers do not make for good kernel-doc candidates
 - Kernel-doc header lines should start with " *"
 - Fix doc-rot issue

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

 drivers/net/wireless/rsi/rsi_91x_sdio.c:25: warning: cannot understand function prototype: 'u16 dev_oper_mode = DEV_OPMODE_STA_BT_DUAL; '
 drivers/net/wireless/rsi/rsi_91x_sdio.c:802: warning: bad line:                                    from the device.
 drivers/net/wireless/rsi/rsi_91x_sdio.c:842: warning: Function parameter or member 'pfunction' not described in 'rsi_init_sdio_interface'
 drivers/net/wireless/rsi/rsi_91x_sdio.c:842: warning: Excess function parameter 'pkt' description in 'rsi_init_sdio_interface'

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/20200826093401.1458456-17-lee.jones@linaro.org