spi: tegra20_sflash: Remove redundant code to set bus and cs of struct spi_slave

It's done in spi_alloc_slave(), thus remove the redundant code.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Acked-by: NMarek Vasut <marex@denx.de>
Reviewed-by: NJagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>

drivers/spi/tegra20_sflash.c

@@ -132,8 +132,6 @@ struct spi_slave *tegra20_spi_setup_slave(unsigned int bus, unsigned int cs,
 		printf("SPI error: malloc of SPI structure failed\n");
 		return NULL;
 	}
-	spi->slave.bus = bus;
-	spi->slave.cs = cs;
 	spi->ctrl = &spi_ctrls[bus];
 	if (!spi->ctrl) {
 		printf("SPI error: could not find controller for bus %d\n",