sunxi: Kconfig: rename non-existent SUN50I_A64 config symbol

There is no "CONFIG_MACH_SUN50I_A64" in upstream U-Boot, so fix
the name to prevent the option to be enabled.
Signed-off-by: NAndre Przywara <andre.przywara@arm.com>
Reviewed-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>

board/sunxi/Kconfig

@@ -426,7 +426,7 @@ config AXP_GPIO
 
 config VIDEO
 	bool "Enable graphical uboot console on HDMI, LCD or VGA"
-	depends on !MACH_SUN8I_A83T && !MACH_SUN8I_H3 && !MACH_SUN9I && !MACH_SUN50I_A64
+	depends on !MACH_SUN8I_A83T && !MACH_SUN8I_H3 && !MACH_SUN9I && !MACH_SUN50I
 	default y
 	---help---
 	Say Y here to add support for using a cfb console on the HDMI, LCD