dt-bindings: i2c: Rewrite Nomadik I2C bindings in YAML

This rewrites the Nomadik I2C bindings in YAML, some extra
tweaks were needed because of the way the original nomadik
names the compatible with two compatibles and the DB8500
with three, and the two main variants use a different clock
name.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>