ARM: dts: rockchip: remove disable-wp from rv1108-elgin-r1 emmc node

The mmc.txt didn't explicitly say disable-wp is for SD card slot only,
but that is what it was designed for in the first place.
Remove all disable-wp from emmc or sdio controllers.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>