Fix OMAP EHCI suspend/resume failure (i693)

Its observed with some PHY, the 60Mhz clock gets
cut too soon for OMAP EHCI, leaving OMAP-EHCI in a bad state.

So on starting port suspend, make sure the 60Mhz clock to EHCI
is kept alive using an internal clock, so that EHCi can cleanly
transition its hw state machine on a port suspend.

Its not proven if this is the issue hit on USB3333,
but the symptoms look very similar.

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Volodymyr Mieshkov <x0182794@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>