sunxi: Add default MMC0 card detect pin for A83T, H3 and A64 SoCs

A83T, H3, and A64 have a dedicated pin for card detect on the PF
pingroup. This is used in all designs. Set it as the default.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Reviewed-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>

board/sunxi/Kconfig

@@ -260,6 +260,7 @@ config MMC
 
 config MMC0_CD_PIN
 	string "Card detect pin for mmc0"
+	default "PF6" if MACH_SUN8I_A83T || MACH_SUN8I_H3 || MACH_SUN50I
 	default ""
 	---help---
 	Set the card detect pin for mmc0, leave empty to not use cd. This