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

drivers/dma/at_hdmac.c

@@ -656,7 +656,7 @@ static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
 
 /**
  * atc_tx_submit - set the prepared descriptor(s) to be executed by the engine
- * @desc: descriptor at the head of the transaction chain
+ * @tx: descriptor at the head of the transaction chain
  *
  * Queue chain if DMA engine is working already
  *
@@ -1196,7 +1196,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 	return NULL;
 }
 
-/**
+/*
  * atc_dma_cyclic_check_values
  * Check for too big/unaligned periods and unaligned DMA buffer
  */
@@ -1217,7 +1217,7 @@ atc_dma_cyclic_check_values(unsigned int reg_width, dma_addr_t buf_addr,
 	return -EINVAL;
 }
 
-/**
+/*
  * atc_dma_cyclic_fill_desc - Fill one period descriptor
  */
 static int