The vpumix power domain has a reset assigned to it, however
when used, it causes a system hang.  Testing has shown that
it does not appear to be needed anywhere.

Fixes: d39d4bb1 ("arm64: dts: imx8mm: add GPC node")
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>