arm64: dts: meson-g12a-sei510: add 32k clock to bluetooth node

The 32k low power clock is necessary for the bluetooth part of the
combo module to initialize correctly, simply add the same clock we
use for the sdio pwrseq.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>