spi: txx9: Let spi core handle validating transfer length

spi core will handle validating transfer length since commit 4d94bd21b333
"spi: core: Validate length of the transfers in message".
So remove the same checking in this driver.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-txx9.c

@@ -306,12 +306,8 @@ static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m)
 
 	/* check each transfer's parameters */
 	list_for_each_entry(t, &m->transfers, transfer_list) {
-		u8 bits_per_word = t->bits_per_word;
-
 		if (!t->tx_buf && !t->rx_buf && t->len)
 			return -EINVAL;
-		if (t->len & ((bits_per_word >> 3) - 1))
-			return -EINVAL;
 	}
 
 	spin_lock_irqsave(&c->lock, flags);