spi: stm32: remove inexistant variables in struct stm32_spi_cfg comment

Variables 'can_dma' and 'has_startbit' are described within the
struct stm32_spi_cfg comment but have never existed in this structure
so remove them.
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/20220119093245.624878-2-alain.volmat@foss.st.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-stm32.c

@@ -221,7 +221,6 @@ struct stm32_spi;
  * time between frames (if driver has this functionality)
  * @set_number_of_data: optional routine to configure registers to desired
  * number of data (if driver has this functionality)
- * @can_dma: routine to determine if the transfer is eligible for DMA use
  * @transfer_one_dma_start: routine to start transfer a single spi_transfer
  * using DMA
  * @dma_rx_cb: routine to call after DMA RX channel operation is complete
@@ -232,7 +231,6 @@ struct stm32_spi;
  * @baud_rate_div_min: minimum baud rate divisor
  * @baud_rate_div_max: maximum baud rate divisor
  * @has_fifo: boolean to know if fifo is used for driver
- * @has_startbit: boolean to know if start bit is used to start transfer
  */
 struct stm32_spi_cfg {
 	const struct stm32_spi_regspec *regs;