greybus: arche-platform: Convert delayed work to do only hub3613 configuration

This is preparation of interrupt handling support, where APB coldboot
and wake/detect handling will be handled as response to wake/detect
interrupt.
Due to slower I2C write operations in HUB configuration, it is important
to separate HUB configuration, and probably delay it after APB is
cold booted.

Note that delayed work will be scheduled from interrupt handler,
in following patches.

To satisfy build (and bisect), remove apb_cold_boot() fn, which will be
added back in the patch where it gets used again.

Testing Done: Tested on DB3.5 platform.

Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Reviewed-by: Michael Scott <michael.scott@linaro.org>
Tested-by: Michael Scott <michael.scott@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>