configs: enable poweroff command on QEMU ARM platforms

Enable the sysreset based poweroff command. It invokes PSCI.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/qemu_arm_defconfig b/configs/qemu_arm_defconfig
index 6373185..f0ee546 100644
--- a/configs/qemu_arm_defconfig
+++ b/configs/qemu_arm_defconfig
@@ -65,6 +65,7 @@
 CONFIG_DEBUG_UART_PL011=y
 CONFIG_DEBUG_UART_SHIFT=2
 CONFIG_SYSRESET=y
+CONFIG_SYSRESET_CMD_POWEROFF=y
 CONFIG_SYSRESET_PSCI=y
 CONFIG_TPM2_MMIO=y
 CONFIG_USB=y