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/zynq_cse_qspi_defconfig b/configs/zynq_cse_qspi_defconfig
index 86c5d44..9659fae 100644
--- a/configs/zynq_cse_qspi_defconfig
+++ b/configs/zynq_cse_qspi_defconfig
@@ -2,6 +2,7 @@
 CONFIG_SYS_CONFIG_NAME="zynq_cse"
 CONFIG_ARCH_ZYNQ=y
 CONFIG_SYS_TEXT_BASE=0xFFFC0000
+CONFIG_SPL_STACK_R_ADDR=0x200000
 # CONFIG_ZYNQ_DDRC_INIT is not set
 CONFIG_DEFAULT_DEVICE_TREE="zynq-cse-qspi-single"
 CONFIG_DEBUG_UART=y
@@ -9,6 +10,7 @@
 CONFIG_BOOTDELAY=-1
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_SPL=y
+CONFIG_SPL_STACK_R=y
 CONFIG_SYS_PROMPT="Zynq> "
 # CONFIG_CMD_BDI is not set
 # CONFIG_CMD_CONSOLE is not set