spi: spi-davinci: Fix a few kerneldoc misspellings and API slippages

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

 drivers/spi/spi-davinci.c:249: warning: Function parameter or member 'dspi' not described in 'davinci_spi_get_prescale'
 drivers/spi/spi-davinci.c:249: warning: Function parameter or member 'max_speed_hz' not described in 'davinci_spi_get_prescale'
 drivers/spi/spi-davinci.c:249: warning: Excess function parameter 'maxspeed_hz' description in 'davinci_spi_get_prescale'
 drivers/spi/spi-davinci.c:719: warning: Function parameter or member 'data' not described in 'dummy_thread_fn'
 drivers/spi/spi-davinci.c:719: warning: Excess function parameter 'context_data' description in 'dummy_thread_fn'
 drivers/spi/spi-davinci.c:735: warning: Function parameter or member 'data' not described in 'davinci_spi_irq'
 drivers/spi/spi-davinci.c:735: warning: Excess function parameter 'context_data' description in 'davinci_spi_irq'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200717135424.2442271-4-lee.jones@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-davinci.c

@@ -236,7 +236,8 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value)
 
 /**
  * davinci_spi_get_prescale - Calculates the correct prescale value
- * @maxspeed_hz: the maximum rate the SPI clock can run at
+ * @dspi: the controller data
+ * @max_speed_hz: the maximum rate the SPI clock can run at
  *
  * This function calculates the prescale value that generates a clock rate
  * less than or equal to the specified maximum.
@@ -711,7 +712,7 @@ err_desc:
 /**
  * dummy_thread_fn - dummy thread function
  * @irq: IRQ number for this SPI Master
- * @context_data: structure for SPI Master controller davinci_spi
+ * @data: structure for SPI Master controller davinci_spi
  *
  * This is to satisfy the request_threaded_irq() API so that the irq
  * handler is called in interrupt context.
@@ -724,7 +725,7 @@ static irqreturn_t dummy_thread_fn(s32 irq, void *data)
 /**
  * davinci_spi_irq - Interrupt handler for SPI Master Controller
  * @irq: IRQ number for this SPI Master
- * @context_data: structure for SPI Master controller davinci_spi
+ * @data: structure for SPI Master controller davinci_spi
  *
  * ISR will determine that interrupt arrives either for READ or WRITE command.
  * According to command it will do the appropriate action. It will check