sunxi: mmc: Set CONFIG_SYS_MMC_MAX_DEVICE

Set CONFIG_SYS_MMC_MAX_DEVICE to 4 for sunxi SoC.
This define is needed in the API code.

Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h
index 2e02f8c..b0bfc0d 100644
--- a/include/configs/sunxi-common.h
+++ b/include/configs/sunxi-common.h
@@ -145,6 +145,7 @@
 #define CONFIG_MMC_SUNXI_SLOT		0
 #define CONFIG_ENV_IS_IN_MMC
 #define CONFIG_SYS_MMC_ENV_DEV		0	/* first detected MMC controller */
+#define CONFIG_SYS_MMC_MAX_DEVICE	4
 #endif
 
 /* 64MB of malloc() pool */