ipq40xx: use DTSI for Jalapeno

Lets move common code for Jalapeno into DTSI, this way Jalapeno based
boards don't introduce duplicate code.

While at it, lets also fix some style issues and update to current DTS
style.

Signed-off-by: Robert Marko <robert@meshpoint.me>
[commit description long line wrap]
Signed-off-by: Petr Štetiar <ynezz@true.cz>