ARM: dts: allwinner: Split out non-SoC specific parts of Neutis N5

A new variant of Emlid Neutis has been inroduced. This one uses H3
instead of H5. The boards are essentially the same. This commit moves
non-SoC-specific parts out so that the common parts could be reused with
ease.

Signed-off-by: Georgii Staroselskii <georgii.staroselskii@emlid.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>