arm64: dts: rockchip: Remove undocumented supports-emmc property

arm64: dts: rockchip: Remove undocumented supports-emmc property

supports-emmc is an undocumented property that slipped into the mainline
kernel devicetree for some boards. Drop it.

Fixes: c484cf93f61b ("arm64: dts: rockchip: add PX30-µQ7 (Ringneck) SoM with Haikou baseboard")
Cc: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Fixes: b8c028782922 ("arm64: dts: rockchip: Add DTS for FriendlyARM NanoPi R2S Plus")
Cc: Sergey Bostandzhyan <jin@mediatomb.cc>
Fixes: 8d94da58de53 ("arm64: dts: rockchip: Add EmbedFire LubanCat 1")
Cc: Wenhao Cui <lasstp5011@gmail.com>
Fixes: cdf46cdbabfc ("arm64: dts: rockchip: Add dts for EmbedFire rk3568 LubanCat 2")
Cc: Andy Yan <andyshrk@163.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20241008203940.2573684-6-heiko@sntech.de
Signed-off-by: Heiko Stuebner <heiko@sntech.de>