ARM: dts: at91: at91sam9g25ek: fix I2C bus unit address

w+arch/arm/dts/.at91sam9g25ek.dtb.pre.tmp:28.25-47.7: Warning (i2c_bus_reg): /ahb/apb/i2c@f8010000/camera@0x30: I2C bus unit address format error, expected "30"

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>