ARM64: dts: meson-gx: grow reset controller memory zone

Now the Amlogic Meson GX SoCs datasheet documents all the Reset registers,
grow the memory in the node to allow usage of the level registers.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>