dmaengine: at_hdmac: Repair parameter misspelling and demote non-kerneldoc headers

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

 drivers/dma/at_hdmac.c:666: warning: Function parameter or member 'tx' not described in 'atc_tx_submit'
 drivers/dma/at_hdmac.c:666: warning: Excess function parameter 'desc' description in 'atc_tx_submit'
 drivers/dma/at_hdmac.c:1206: warning: Function parameter or member 'reg_width' not described in 'atc_dma_cyclic_check_values'
 drivers/dma/at_hdmac.c:1206: warning: Function parameter or member 'buf_addr' not described in 'atc_dma_cyclic_check_values'
 drivers/dma/at_hdmac.c:1206: warning: Function parameter or member 'period_len' not described in 'atc_dma_cyclic_check_values'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'chan' not described in 'atc_dma_cyclic_fill_desc'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'desc' not described in 'atc_dma_cyclic_fill_desc'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'period_index' not described in 'atc_dma_cyclic_fill_desc'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'buf_addr' not described in 'atc_dma_cyclic_fill_desc'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'reg_width' not described in 'atc_dma_cyclic_fill_desc'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'period_len' not described in 'atc_dma_cyclic_fill_desc'
 drivers/dma/at_hdmac.c:1228: warning: Function parameter or member 'direction' not described in 'atc_dma_cyclic_fill_desc'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Link: https://lore.kernel.org/r/20200714111546.1755231-9-lee.jones@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>