arm64: dts: rockchip: remove num-slots property from rk3328-nanopi-r2s-plus

arm64: dts: rockchip: remove num-slots property from rk3328-nanopi-r2s-plus

num-slots was not part of the dw-mmc binding and the last slipage of
one of them seeping in from the vendor kernel was removed way back in
2017. Somehow the nanopi-r2s-plus managed to smuggle another on in the
kernel, so remove that as well.

Fixes: b8c028782922 ("arm64: dts: rockchip: Add DTS for FriendlyARM NanoPi R2S Plus")
Cc: Sergey Bostandzhyan <jin@mediatomb.cc>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20241008203940.2573684-9-heiko@sntech.de
Signed-off-by: Heiko Stuebner <heiko@sntech.de>