ARM: OMAP: beagle: Set USB Host Port 1 to OMAP_USBHS_PORT_MODE_UNUSED

The beagleboard USB Host Port that is used is Port 2. The platform driver
sets MODE_PHY for port 1 causing pin muxing to override the pins on the
expansion connector P17 when using board_mux[]. Since USBHS Port 1 is not
connected remove the case for muxing the USB Port1 pins by default.

Tested with BeagleBoard xM revC and checked the userguides for Beagle xM
and revC to be sure USB Port2 is what is used.

Signed-off-by: Brian Austin <brian.austin@cirrus.com>
Acked-by: Russ Dill <Russ.Dill@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>