spi: at91-usart: Remove duplicated checking for spi->bits_per_word

This checking is already done in __spi_validate_bits_per_word().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
1 file changed