spi: fsl-spi: No need to check transfer length versus word size

The verification is already do in the SPI core by function
__spi_validate(), not it to check it again in fsl_spi_bufs().

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/9ace69a8085e22fafd9159e99edd7bbfae2f9940.1680371809.git.christophe.leroy@csgroup.eu


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