spi: fsl-espi: remove usage of 'delay_usecs' field

The 'delay_usecs' field is being removed from the spi_transfer struct.
This change removes it from the SPI FSL ESPI driver.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210308145502.1075689-9-aardelean@deviqon.com


Signed-off-by: Mark Brown <broonie@kernel.org>