usb: ehci-omap: Reset the USB Host OMAP module

usb: ehci-omap: Reset the USB Host OMAP module

In commit bb1f327 we removed the UHH reset to fix NFS root (over usb
ethernet) problems with Beagleboard (3530 ES1.0). However, this
seems to cause USB detection problems for Pandaboard, about (3/8).

On further investigation, it seems that doing the UHH reset is not
the cause of the original Beagleboard problem, but in the way the reset
was done.

This patch adds proper UHH RESET mechanism for OMAP3 and OMAP4/5 based
on the UHH_REVISION register. This should fix the Beagleboard NFS
problem as well as the Pandaboard USB detection problem.

Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
CC: Stefan Roese <sr@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Roger Quadros <rogerq@ti.com>