arm64: dts: amlogic: t7: fix UART clock and SD card recovery

Two fixes found while booting mainline on a Khadas VIM4.

The first one wires uart_a to the real UART bus clock. It was pointed at the 24MHz crystal as a placeholder, because the T7 clock controller driver did not exist when these boards were added. That leaves the real clock without a user, so the kernel turns it off when it disables unused clocks at the end of boot, and the board hangs with the console gone.

The second one drops regulator-always-on from the SD card supply. A card that refuses the 1.8V UHS switch can only be recovered by removing its power, which that property prevents, so the card never initialises and the MMC core retries forever.

Both were tested on a Khadas VIM4 booting v7.2 from the SD card.

Changes in v2:
- Update UART clocks directly in the board DTS files instead of moving them to amlogic-t7.dtsi, as &xtal is defined at the board level.

Lucas Tanure (2):
arm64: dts: amlogic: t7: use the real UART pclk
arm64: dts: amlogic: t7: khadas-vim4: allow the SD card to be power
cycled

 arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-an400.dts       | 2 +-
 arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

2.55.0