usb: phy: samsung: Add support to set pmu isolation

Adding support to parse device node data in order to get
required properties to set pmu isolation for usb-phy.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>