ARM: dts: sun8i: BPI-M2M: Remove i2c nodes

The i2c nodes were pre-populated to ease the use of overlays. However, now
that we provide default muxing options for those nodes, the one in the DTS
don't provide any content at all.

Remove them.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>