ARM: OMAP1: fix USB configuration for device-only setups

Currently we do USB configuration only if the host mode (CONFIG_USB)
is enabled. But it should be done also in the case of device-only setups,
so change the condition to CONFIG_USB_SUPPORT. This allows to use
omap_udc on Palm Tungsten E.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Tony Lindgren <tony@atomide.com>