ARM: at91/at91sam9x5ek: i2c1 and i2c2 conflict with macb and lcd

On at91sam9x5ek, macb0 is enabled, so it conflicts with i2c2 (PB4)
same for i2c1, (conflicts with LCD).
Moreover, only i2c0 is used on this board.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>