omap3_logic: Move SPL Stack into SDRAM

A previous patch broke the board. This patch will add missing part
from the previous patch and also move the SPL Stack into SDRAM at
0x82000000.

Tested with GCC 4.8.2 and GCC 6.2

Fixes: 0959649d ("omap3_logic: Switch to simple malloco in SPL")
Signed-off-by: NAdam Ford <aford173@gmail.com>

Changes in V2:
  - Keep CONFIG_SPL_SYS_MALLOC_SIMPLE
  - Add CONFIG_SYS_MALLOC_F_LEN=0x2000 (8 MB)

configs/omap3_logic_defconfig

@@ -6,6 +6,9 @@ CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_VERSION_VARIABLE=y
 CONFIG_SPL=y
 CONFIG_SPL_SYS_MALLOC_SIMPLE=y
+CONFIG_SPL_STACK_R_ADDR=0x82000000
+CONFIG_SPL_STACK_R=y
+CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_SPL_MTD_SUPPORT=y
 CONFIG_SPL_OS_BOOT=y
 CONFIG_HUSH_PARSER=y