Introduce a new sysreset driver for the QEMU Virtual System Controller.
This device is found on QEMU "virt" machines (such as the m68k virt
target) and provides a mechanism to trigger system reset and power-off
events.
The driver maps U-Boot sysreset types to the corresponding controller
commands:
- SYSRESET_WARM / SYSRESET_COLD -> VIRT_CTRL_CMD_RESET
- SYSRESET_POWER_OFF -> VIRT_CTRL_CMD_HALT
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reviewed-by: Simon Glass <simon.glass@canonical.com>