[ARM] pxa/cm-x300: enable USB port 2 for PXA300

Port 2 requires setting of UP2OCR register to function as USB host.

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>