Revert "arm64: dts: imx8mn-venice-gw7902: disable gpu"

This reverts commit 0c566618

,
this one was meant for v5.18, not as a bugfix, though the
patch itself was correct.

Reported-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>