libertas_tf: Fix a bunch of function doc formatting issues

libertas_tf: Fix a bunch of function doc formatting issues

Kerneldoc expects attributes/parameters to be in '@*.: ' format and
gets confused if the variable does not follow the type/attribute
definitions.

Also demote one stray non-kernel-doc header.

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

 drivers/net/wireless/marvell/libertas_tf/cmd.c:44: warning: Function parameter or member 'priv' not described in 'lbtf_cmd_copyback'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:44: warning: Function parameter or member 'extra' not described in 'lbtf_cmd_copyback'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:44: warning: Function parameter or member 'resp' not described in 'lbtf_cmd_copyback'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:80: warning: Function parameter or member 'priv' not described in 'lbtf_update_hw_spec'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:150: warning: Function parameter or member 'priv' not described in 'lbtf_set_channel'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:150: warning: Function parameter or member 'channel' not described in 'lbtf_set_channel'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:277: warning: Function parameter or member 'priv' not described in '__lbtf_cleanup_and_insert_cmd'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:277: warning: Function parameter or member 'cmdnode' not described in '__lbtf_cleanup_and_insert_cmd'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:442: warning: Function parameter or member 'priv' not described in 'lbtf_allocate_cmd_buffer'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:490: warning: Function parameter or member 'priv' not described in 'lbtf_free_cmd_buffer'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:527: warning: Function parameter or member 'priv' not described in 'lbtf_get_cmd_ctrl_node'
 drivers/net/wireless/marvell/libertas_tf/cmd.c:561: warning: Function parameter or member 'priv' not described in 'lbtf_execute_next_command'

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/20200819072402.3085022-8-lee.jones@linaro.org