OMAP: USB : Fix the EHCI enumeration and core retention issue

This commit 354ab856 titled
"Fix OMAP EHCI suspend/resume failure (i693)" is causing
the usb hub and device detection fails in beagle XM
causeing NFS not functional. This affects the core retention too.
The same commit logic needs to be revisted adhering to hwmod and
device tree framework.
for now, this commit id 354ab856
titled "Fix OMAP EHCI suspend/resume failure (i693)" reverted.

This patch is validated on BeagleXM with NFS support over
usb ethernet and USB mass storage and other device detection.

Signed-off-by: Keshava Munegowda <keshava_mgowda@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Cc: stable <stable@vger.kernel.org> # 3.5
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>