phy: core: Let node ptr of PHY point to PHY and not of PHY provider

phy: core: Let node ptr of PHY point to PHY and not of PHY provider

In case of multi-phy PHY providers, each PHY should be modeled as a sub
node of the PHY provider. Then each PHY will have a different node pointer
(node pointer of sub node) than that of PHY provider. Added this provision
in the PHY core.
Also fixed all drivers to use the updated API.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
(cherry picked from commit f0ed817638b59aa927f1f7e9564dd8796b18dc4f)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Conflicts:
	drivers/phy/phy-berlin-sata.c
	drivers/phy/phy-exynos5-usbdrd.c
	drivers/phy/phy-exynos5250-sata.c
	drivers/phy/phy-hix5hd2-sata.c
	drivers/phy/phy-qcom-apq8064-sata.c
	drivers/phy/phy-samsung-usb2.c
	drivers/phy/phy-sun4i-usb.c
	drivers/phy/phy-ti-pipe3.c
	drivers/phy/phy-xgene.c