arm64: dts: meson-g12b: move G12B thermal nodes to meson-g12b.dtsi

The G12B thermal nodes should be in the meson-g12b.dtsi file.

Fixes: 195f1403 ("arm64: dts: meson: g12b: add cooling properties")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200512093916.19676-2-narmstrong@baylibre.com