Add the exynos-pcie-phy binding for Exynos PCIe PHY.  This is for using
generic PHY framework.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRob Herring <robh@kernel.org>