arm64: dts: amlogic: g12: assign the MMC A signal clock

arm64: dts: amlogic: g12: assign the MMC A signal clock

The amlogic MMC driver operate with the assumption that MMC clock
is configured to provide 24MHz. It uses this path for low
rates such as 400kHz.

Assign the clock to make sure it is properly configured

Fixes: 8a6b3ca2d361 ("arm64: dts: meson: g12a: add SDIO controller")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260114-amlogic-mmc-clocks-followup-v1-6-a999fafbe0aa@baylibre.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>