usb: pd: add snapshot of qpnp-pdphy and policy_engine drivers

The qpnp-pdphy driver provides support for the PD PHY peripheral.
This along with the policy engine provides a protocol stack that
supports USB Power Delivery communication over a Type-C port.
This snapshot is taken as of msm-4.14 commit <2fe3bbf5400>
("Merge "clk: qcom: Add support for GCC_USB3_PHY_PRIM_SP0_BCR"").
Refactored driver to reduce cyclomatic complexity of the code.

Change-Id: Iacaf88c874396e49222be3a11e7653e2a4730f9d
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>