USB: EHCI: Add MSM Host Controller driver

This patch adds the support for EHCI compliant HSUSB Host controller found
on MSM chips.  The root hub has a single port and TT is built into it.
This driver depends on OTG driver for PHY initialization, clock
management and powering up VBUS.
This snapshot is taken as of msm-4.14 'commit 86918472c0fd
("ARM: dts: msm: support A/B OTA for LW.2.0")'.

Change-Id: Ia26d85dbf2217d3284660d5cf5cce68fdac274d3
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Swetha Chikkaboraiah <schikk@codeaurora.org>