spi: slave: Fix missing break in switch

Apparently, this code does not actually fall through to the next case
because the machine restarts before it has a chance. However, for the
sake of maintenance and readability, we better add the missing break
statement.

Addresses-Coverity-ID: 1437892 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-slave-system-control.c

@@ -60,6 +60,7 @@ static void spi_slave_system_control_complete(void *arg)
 	case CMD_REBOOT:
 		dev_info(&priv->spi->dev, "Rebooting system...\n");
 		kernel_restart(NULL);
+		break;
 
 	case CMD_POWEROFF:
 		dev_info(&priv->spi->dev, "Powering off system...\n");