ARM: dts: AM33XX: Rename I2C and GPIO nodes

Rename I2C and GPIO nodes according to AM33XX TRM. According to
AM33XX TRM device instances are starting from "0" like i2c0, i2c1
and i2c3.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
[panto@antoniou-consulting.com: initial patch by pantelis's]
Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Signed-off-by: Benoit Cousson <benoit.cousson@linaro.org>