mmc: atmel-mci: Provide 2 new and correct 1 existing property description

'sg_len' and 'dma_conf' are missing correct kerneldoc documentation and
'buf_phys_addr' was misspelled.  Correcting these issues fixes the
following W=1 kernel build issues:

 mmc/host/atmel-mci.c:352: warning: Function parameter or member 'sg_len' not described in 'atmel_mci'
 mmc/host/atmel-mci.c:352: warning: Function parameter or member 'buf_phys_addr' not described in 'atmel_mci'
 mmc/host/atmel-mci.c:352: warning: Function parameter or member 'dma_conf' not described in 'atmel_mci'

Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200701124702.908713-7-lee.jones@linaro.orgSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/atmel-mci.c

@@ -225,12 +225,13 @@ struct atmel_mci_dma {
  * @lock: Spinlock protecting the queue and associated data.
  * @regs: Pointer to MMIO registers.
  * @sg: Scatterlist entry currently being processed by PIO or PDC code.
+ * @sg_len: Size of the scatterlist
  * @pio_offset: Offset into the current scatterlist entry.
  * @buffer: Buffer used if we don't have the r/w proof capability. We
  *      don't have the time to switch pdc buffers so we have to use only
  *      one buffer for the full transaction.
  * @buf_size: size of the buffer.
- * @phys_buf_addr: buffer address needed for pdc.
+ * @buf_phys_addr: buffer address needed for pdc.
  * @cur_slot: The slot which is currently using the controller.
  * @mrq: The request currently being processed on @cur_slot,
  *	or NULL if the controller is idle.
@@ -240,6 +241,7 @@ struct atmel_mci_dma {
  * @data_size: just data->blocks * data->blksz.
  * @dma: DMA client state.
  * @data_chan: DMA channel being used for the current data transfer.
+ * @dma_conf: Configuration for the DMA slave
  * @cmd_status: Snapshot of SR taken upon completion of the current
  *	command. Only valid when EVENT_CMD_COMPLETE is pending.
  * @data_status: Snapshot of SR taken upon completion of the current