MSM: Add USB support for MSM7x30

Add USB OTG, peripheral and host devices.  This patch also adds
usb_phy_clk which is required for resetting the PHY.  VBUS power up
and shutdown routines depends on PMIC module.  As PMIC driver is
unavailable, configure USB in peripheral only mode.

Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>