ARM: dts: sun8i: h3: Remove unnecessary reserved memory node

Just like on the A33, the video engine on the H3 can map any address in
memory, so there is no particular need to have reserved memory at a fixed
address.

As a result, remove the reserved memory node and let the kernel allocate
the CMA pool wherever it sees fit.

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