USB: host: Remove hard-coded octeon platform information for ehci/ohci

Instead rely on device tree information for ehci and ohci.

This was suggested with
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=1401358203-60225-4-git-send-email-alex.smith%40imgtec.com

  "The device tree will *always* have correct ehci/ohci clock
  configuration, so use it.  This allows us to remove a big chunk of
  platform configuration code from octeon-platform.c."

More or less I rebased that patch on Alan's work to remove ehci-octeon
and ohci-octeon drivers.

Cc: David Daney <david.daney@cavium.com>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-platform.c

@@ -353,6 +353,7 @@ static const struct of_device_id vt8500_ehci_ids[] = {
 	{ .compatible = "via,vt8500-ehci", },
 	{ .compatible = "wm,prizm-ehci", },
 	{ .compatible = "generic-ehci", },
+	{ .compatible = "cavium,octeon-6335-ehci", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, vt8500_ehci_ids);