hw/misc/max111x: provide QOM properties for setting initial values

hw/misc/max111x: provide QOM properties for setting initial values

Add some QOM properties to the max111x ADC device to allow the
initial values to be configured. Currently this is done by
board code calling max111x_set_input() after it creates the
device, which doesn't work on system reset.

This requires us to implement a reset method for this device,
so while we're doing that make sure we reset the other parts
of the device state.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20200628142429.17111-7-peter.maydell@linaro.org