usb: gadget: fix Kconfig warning

warning: (USB_MUSB_HDRC_HCD && USB_SUPPORT && USB_MUSB_HDRC &&
(USB_MUSB_HOST || USB_MUSB_OTG) && USB_GADGET_MUSB_HDRC || USB_MUSB_OTG
&& <choice> && USB && USB_GADGET && PM && EXPERIMENTAL) selects USB_OTG
which has unmet direct dependencies (USB_GADGET_OMAP && ARCH_OMAP_OTG &&
USB_OHCI_HCD)

This doesn't seem to happen on 2.6.36-rc8, but still doesn't make sense
to keep this duplicated config that is already defined in usb/core.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>