rockchip: rk3399: correct SPL_MAX_SIZE

The SPL_MAX_SIZE is the internal memory size minux the space
used by bootrom.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/include/configs/rk3399_common.h b/include/configs/rk3399_common.h
index 7a8a442..44dad57 100644
--- a/include/configs/rk3399_common.h
+++ b/include/configs/rk3399_common.h
@@ -31,7 +31,7 @@
 #define CONFIG_SYS_LOAD_ADDR		0x00800800
 #define CONFIG_SPL_STACK		0xff8effff
 #define CONFIG_SPL_TEXT_BASE		0xff8c2000
-#define CONFIG_SPL_MAX_SIZE		0x30000
+#define CONFIG_SPL_MAX_SIZE		0x30000 - 0x2000
 /*  BSS setup */
 #define CONFIG_SPL_BSS_START_ADDR       0xff8e0000
 #define CONFIG_SPL_BSS_MAX_SIZE         0x10000