USB: Add MSM OTG Controller driver

This driver implements PHY initialization, clock management, ULPI IO ops
and simple OTG state machine to kick host/peripheral based on Id/VBUS
line status.  VBUS/Id lines are tied to a reference voltage on some boards.
Hence provide debugfs interface to select host/peripheral mode.

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