ARM: ohci-pxa27x: enable OHCI over U2DC for pxa3xx

U2D Controller of pxa3xx is able to work in host mode.
Make pxa specific ohci implementation aware of it.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>