usb: Select USB_MUSB_DSPS with USB_MUSB_TI

usb: Select USB_MUSB_DSPS with USB_MUSB_TI

USB_MUSB_TI requires USB_MUSB_DSPS, failing at link time if it's not
selected:

  drivers/usb/musb-new/built-in.o: In function `ti_musb_host_ofdata_to_platdata':
  drivers/usb/musb-new/ti-musb.c:193: undefined reference to `musb_dsps_ops'

or if OF_CONTROL is not selected:

  arch/arm/mach-omap2/built-in.o:(.data.usb0+0x24): undefined reference to `musb_dsps_ops'

Reviewed-by: Hannes Schmelzer <oe5hpm@oevsv.at>
Tested-by: Hannes Schmelzer <oe5hpm@oevsv.at>
Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>