spi: stm32: Revert "properly handle 0 byte transfer"

0 byte transfer handling is now done within the core in code added
by commit b306320322 ("spi: Skip zero-length transfers in spi_transfer_one_message()")

This reverts commit 2269f5a8b1 ("spi: stm32: properly handle 0 byte transfer")

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-5-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-stm32.c

@@ -1647,10 +1647,6 @@ static int stm32_spi_transfer_one(struct spi_master *master,
 	struct stm32_spi *spi = spi_master_get_devdata(master);
 	int ret;
 
-	/* Don't do anything on 0 bytes transfers */
-	if (transfer->len == 0)
-		return 0;
-
 	spi->tx_buf = transfer->tx_buf;
 	spi->rx_buf = transfer->rx_buf;
 	spi->tx_len = spi->tx_buf ? transfer->len : 0;