USB: EHCI: Add MSM Host Controller driver

This patch adds 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.

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>