uboot-imx

at91: Get rid of some warnings when building for otc570

The soft-i2c code for AT91 defines I2C_SOFT_DECLARATIONS
for direct access by dereferencing a pio pointer.
The OTC570 platform uses the AT91 gpio API so it does not
need the pio variable.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>