dwc3: Add support for setting USB control registers as phy platform data

dwc3: Add support for setting USB control registers as phy platform data

This patch adds support for setting USB vendor specific control registers
as phy platform data. These registers are used by the phy to configure USB
PIPE signals.

Note:
This patch is a temporary workaround which is done to set pipe signals
without effecting usb cci and this will be redesigned. this change will
get it into v2017.1 and expected to change once the proper solution is
available.

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>