usb: exynos: add support for getting PHYs from the standard dt array

usb: exynos: add support for getting PHYs from the standard dt array

Add the code for getting generic PHYs from standard device tree array
from the main controller device node. This is a first step in resolving
the conflict between Exynos EHCI/OHCI sub-nodes and generic USB device
bindings. Later the sub-nodes currently used for assigning PHYs to root
ports of the controller will be removed making a place for the generic
USB device bindings nodes.

Suggested-by: Måns Rullgård <mans@mansr.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20190726081453.9456-3-m.szyprowski@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>