arm: zynq: Fix SPL SD boot mode

This patch is fixing two issues:
1. Insufficient stack size for fat fs buffers
2. Insufficient space in malloc area

Tested on zc702 and zc706.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/topic_miamiplus_defconfig b/configs/topic_miamiplus_defconfig
index b511077..d511a94 100644
--- a/configs/topic_miamiplus_defconfig
+++ b/configs/topic_miamiplus_defconfig
@@ -3,12 +3,14 @@
 CONFIG_SYS_CONFIG_NAME="topic_miami"
 CONFIG_ARCH_ZYNQ=y
 CONFIG_SYS_TEXT_BASE=0x4000000
+CONFIG_SPL_STACK_R_ADDR=0x200000
 CONFIG_BOOT_INIT_FILE="board/topic/zynq/zynq-topic-miamiplus/ps7_regs.txt"
 CONFIG_DEFAULT_DEVICE_TREE="zynq-topic-miamiplus"
 CONFIG_DEBUG_UART=y
 CONFIG_BOOTDELAY=0
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_SPL=y
+CONFIG_SPL_STACK_R=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="zynq-uboot> "
 CONFIG_CMD_THOR_DOWNLOAD=y