chameleonv3: Convert CONFIG_SPL_MAX_SIZE to Kconfig

This file was missed during the conversion process. Add the symbol to
defconfig.

Signed-off-by: Paweł Anikiel <pan@semihalf.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/socfpga_chameleonv3_defconfig b/configs/socfpga_chameleonv3_defconfig
index 5d08fd2..41231e2 100644
--- a/configs/socfpga_chameleonv3_defconfig
+++ b/configs/socfpga_chameleonv3_defconfig
@@ -5,6 +5,7 @@
 CONFIG_ENV_OFFSET=0x4400
 CONFIG_DEFAULT_DEVICE_TREE="socfpga_arria10_chameleonv3_480_2"
 CONFIG_SPL_TEXT_BASE=0xFFE00000
+CONFIG_SPL_MAX_SIZE=0x40000
 CONFIG_SPL_DRIVERS_MISC=y
 CONFIG_TARGET_SOCFPGA_CHAMELEONV3=y
 CONFIG_SPL_FS_EXT4=y