arm64: dts: exynos: Make TM2 and TM2E independent from each other

arm64: dts: exynos: Make TM2 and TM2E independent from each other

Currently TM2E dts includes TM2 but there are some differences
between the two boards and TM2 has some properties that TM2E
doesn't have.

That's why it's important to keep the two dts files independent
and put all the commonalities in a tm2-common.dtsi file.

At the current status the only two differences between the two
dts files (besides the board name) are ldo31 and ldo38.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>