rockchip: backport upstream fix R76S SD suspend power loss

rockchip: backport upstream fix R76S SD suspend power loss

This patch is a full backport of Linux upstream commit a9c1acebfe0484343a443d082e039ca77186ed22
for rk3576-nanopi-r76s.dts device tree, resolving SD card power dropout in runtime suspend.

When runtime suspend is active, the SD power domain is shut down, wiping power control
registers and cutting card power. I/O recovery relies on mmc_blk_mq_rw_recovery(),
which results in poor performance and unstable card detection.

Implement GPIO-controlled vcc3v3_sd regulator and attach vmmc-supply to sdmmc node
to maintain SD power during suspend. Also add cd-gpios to guarantee working hotplug
when system enters idle/suspend state.

Modifications in DTS:
- vcc3v3_sd fixed regulator + sdmmc_pwren pinctrl
- vmmc-supply & vqmmc-supply for sdmmc bus power retention
- cd-gpios for SD card presence detection

Signed-off-by: xiao bo <peterwillcn@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/23924
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>