arm64: dts: rockchip: Correct vendor prefix for Hardkernel ODROID-M1

arm64: dts: rockchip: Correct vendor prefix for Hardkernel ODROID-M1

The vendor prefix for Hardkernel ODROID-M1 is incorrectly listed as
rockchip. Use the proper hardkernel vendor prefix for this board, while
at it also drop the redundant soc prefix.

Fixes: fd3583267703 ("arm64: dts: rockchip: Add Hardkernel ODROID-M1 board")
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Link: https://lore.kernel.org/r/20240827211825.1419820-3-jonas@kwiboo.se
Signed-off-by: Heiko Stuebner <heiko@sntech.de>