arm64: allwinner: a64-sopine: Add cd-gpios to mmc0 node

The card detect GPIO for Sopine and Pine64-LTS is PF6.
Add this to the dts.

Signed-off-by: Emmanuel Vadot <manu@freebsd.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>