greybus: interface: avoid I/O to bootrom during removal

Add an interface quirk flag to suppress I/O during interface disable.

This is needed to prevent I/O to the bootrom during controlled
connection tear down (e.g. eject or driver unbind). This will be more
obvious with the new connection tear-down procedure.

Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>