arm64: dts: mt8183: rename rdma fifo size

arm64: dts: mt8183: rename rdma fifo size

property name must include only lowercase and '-'

Fixes: 91f9c963ce79 ("arm64: dts: mt8183: Add display nodes for MT8183")
Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20210128112314.1304160-2-hsinyi@chromium.org
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>