linux-imx

ARM64: dts: meson-gx: Use correct mmc clock source 0

Now that the clock source 0 is properly described in the CCF, use it
instead of assuming the default value (xtal)

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>