drivers: spi: Fix twister build issue

Update spi_bitbang_transceive_async function parameter to it match
with correct one that declared in struct

Signed-off-by: Sadik Ozer <sadik.ozer@analog.com>

drivers/spi/spi_bitbang.c

@@ -231,7 +231,8 @@ static int spi_bitbang_transceive_async(const struct device *dev,
 				    const struct spi_config *spi_cfg,
 				    const struct spi_buf_set *tx_bufs,
 				    const struct spi_buf_set *rx_bufs,
-				    struct k_poll_signal *async)
+				    spi_callback_t cb,
+				    void *userdata)
 {
 	return -ENOTSUP;
 }