riscv: ae350: Increase malloc size for binman spl flow

It will need larger heap size for u-boot-spl to load u-boot.itb which
be generated from binman than USE_SPL_FIT_GENERATOR.

Signed-off-by: Rick Chen <rick@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/ae350_rv32_spl_defconfig b/configs/ae350_rv32_spl_defconfig
index 25b4ada..e8dc816 100644
--- a/configs/ae350_rv32_spl_defconfig
+++ b/configs/ae350_rv32_spl_defconfig
@@ -2,6 +2,7 @@
 CONFIG_SYS_TEXT_BASE=0x01200000
 CONFIG_NR_DRAM_BANKS=2
 CONFIG_ENV_SECT_SIZE=0x1000
+CONFIG_SPL_SYS_MALLOC_F_LEN=0x100000
 CONFIG_SPL=y
 CONFIG_DEFAULT_DEVICE_TREE="ae350_32"
 CONFIG_TARGET_AX25_AE350=y