greybus: arche-platform: Make sure APB power cycles on coldboot

On first wake/detect pulse, everything works fine, as APB would be
in poweroff state initially.
But on subsequent wake/detect pulses, where APB is already in active
state, internal function just returns doing nothing, as it finds that
device is already in active state.

So the solution would be to make sure that, whenever execution reaches
to coldboot, make sure we power cycle it. Power off first, before
powering on.

Interrupt handler takes care of ignoring < 30msec pulses, so we should
be safe here to power cycle APB.

Testing Done: Testd on DB3.5 platform.

Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>