sunxi: enable SPL for sun9i

Now that DRAM initialization and clock setup is supported,
we can enable SPL for the A80.

[wens@csie.org: Added commit message]
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Acked-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>

board/sunxi/Kconfig

@@ -119,6 +119,7 @@ config MACH_SUN9I
 	bool "sun9i (Allwinner A80)"
 	select CPU_V7
 	select SUNXI_GEN_SUN6I
+	select SUPPORT_SPL
 
 config MACH_SUN50I
 	bool "sun50i (Allwinner A64)"