at91: at91-ohci: configure overcurrent pins as input GPIOs

As a new overcurrent_pin[] array has been added to the at91_usbh_data
structure, those pins must be muxed to work properly. This commit
implements this muxing for all AT91 SoCs that support the AT91 OHCI.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[nicolas.ferre@atmel.com: added i variable declaration for the loop]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>