arm64: dts: verdin-imx8mp: fix ctrl_sleep_moci

The GPIO signaling ctrl_sleep_moci is currently handled as a gpio hog.
But the gpio-hog node is made a child of the wrong gpio controller.
Move it to the node representing gpio4 so that it actually works.

Without this carrier board components jumpered to use the signal are
unconditionally switched off.

Fixes: a39ed23b ("arm64: dts: freescale: add initial support for verdin imx8m plus")
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>