usb: ehci-omap: don't complain on -EPROBE_DEFER when no PHY found

Don't complain on -EPROBE_DEFER when no PHY found, the driver
probe will be retried later.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>