greybus: arche-apb-ctrl: Rename internal operational state fns

This is preparation for enabling export set of operational fns
to parent driver.
So it is important to differentiate internal ops function against
externally accessed (from parent).

Testing Done: Tested on EVT1.2 and DB3.5 platform.

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