arm64: dts: mt7986: fix trng node name

arm64: dts: mt7986: fix trng node name

Binding requires node name to be rng not trng:

trng@1020f000: $nodename:0: 'trng@1020f000' does not match '^rng@[0-9a-f]+$'

Fixes: 50137c150f5f ("arm64: dts: mediatek: add basic mt7986 support")
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221027151022.5541-1-linux@fw-web.de
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>