phy: add phy-hi6220-usb

Support hi6220 use phy for HiKey board

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>