arm64: dts: imx8mp: Fix missing microSD slot vqmmc on DH electronics i.MX8M Plus DHCOM

[ Upstream commit c53cf8ce ]

Add missing microSD slot vqmmc-supply property, otherwise the kernel
might shut down LDO5 regulator and that would power off the microSD
card slot, possibly while it is in use. Add the property to make sure
the kernel is aware of the LDO5 regulator which supplies the microSD
slot and keeps the LDO5 enabled.

Fixes: 8d671269 ("arm64: dts: imx8mp: Add support for DH electronics i.MX8M Plus DHCOM and PDK2")
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>