SoM dts has enabled  i2c bus IIC6 (dts i2c5), but defines no aliases.

LX2162A Clearfog dts has aliases for all i2c buses to ensure predictable
numbering for userspace. Add an additional alias for this extra bus.
Signed-off-by: Josua Mayer <josua@solid-run.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>