This property is not defined in binding and driver.

Fixes: 2c002a30 ("arm64: dts: mt7622: add mmc related device nodes")
Fixes: 0b6286dd ("arm64: dts: mt7622: add bananapi BPI-R64 board")
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/20221025132953.81286-6-linux@fw-web.deSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>