arm64: dts: imx8mp-tqma8mpql: fix LDO5 power off

arm64: dts: imx8mp-tqma8mpql: fix LDO5 power off

Fix SD card removal caused by automatic LDO5 power off after boot:

LDO5: disabling
mmc1: card 59b4 removed
EXT4-fs (mmcblk1p2): shut down requested (2)
Aborting journal on device mmcblk1p2-8.
JBD2: I/O error when updating journal superblock for mmcblk1p2-8.

To prevent this, add vqmmc regulator for USDHC, using a GPIO-controlled
regulator that is supplied by LDO5. Since this is implemented on SoM but
used on baseboards with SD-card interface, implement the functionality
on SoM part and optionally enable it on baseboards if needed.

Fixes: 418d1d840e42 ("arm64: dts: freescale: add initial device tree for TQMa8MPQL with i.MX8MP")
Signed-off-by: Markus Niebel <Markus.Niebel@ew.tq-group.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>