greybus: arche-ctrl: Don't expose driver internals to arche-platform driver

We have chosen the *ugly* way of registering two platform drivers from
the module_init() of only one of them, so that we can avoid having two
separate modules for them.

But we should still be doing this in a sane way. There is no need to
expose internals of arche-ctrl to arche-platform, like PM-ops, probe,
resume, id-table, etc. Just expose an init and a exit callback.

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