greybus: arche-apb-ctrl: Re-arrange init sequence

In order to allow APB2 disable by default on boot/init, and also
provide interface to user to enable it later on, re-arrange the init_seq
fn.
The idea here is, the apb_ctrl_init_seq() fn will be renamed to
apb_ctrl_coldboot_seq(), and should not try to claim any resources.
All the resource claim should happen in apb_ctrl_get_devtree_data() fn.

And also uses devm_gpio_request_one() fn wherever possible.

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>