usb: ohci-da8xx: Remove code that references mach

Including mach/* is frowned upon in device drivers, so get rid of it.

This replaces usb20_clk and code that pokes CFGCHIP2 with a proper phy
driver.

Signed-off-by: David Lechner <david@lechnology.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>