Convert CONFIG_SPL_STACK to Kconfig
This converts the following to Kconfig:
CONFIG_SPL_STACK
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/pine64_plus_defconfig b/configs/pine64_plus_defconfig
index dc02ca1..7dbe061 100644
--- a/configs/pine64_plus_defconfig
+++ b/configs/pine64_plus_defconfig
@@ -6,6 +6,7 @@
CONFIG_RESERVE_ALLWINNER_BOOT0_HEADER=y
CONFIG_PINE64_DT_SELECTION=y
# CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+CONFIG_SPL_STACK=0x54000
CONFIG_SYS_PBSIZE=1024
CONFIG_OF_LIST="sun50i-a64-pine64 sun50i-a64-pine64-plus"
CONFIG_PHY_REALTEK=y