Merge pull request #2019 from TomoYamanaka/master_3

Change stack size of main thread for RZ_A1H

Author: sg-

rtos/rtx/TARGET_CORTEX_A/RTX_Conf_CA.c

@@ -72,9 +72,9 @@
 
 //   <o>Main Thread stack size [bytes] <64-4096:8><#/4>
 //   <i> Defines stack size for main thread.
-//   <i> Default: 200
+//   <i> Default: 4096
 #ifndef OS_MAINSTKSIZE
- #define OS_MAINSTKSIZE 2048
+ #define OS_MAINSTKSIZE 4096
 #endif
 
 #ifndef __MBED_CMSIS_RTOS_CA9