phy: Add support for Qualcomm's USB HSIC phy

The HSIC USB controller on qcom SoCs has an integrated all
digital phy controlled via the ULPI viewport.

Cc: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>