py: Move stack_ctrl_init() to mp_init().

As stack checking is enabled by default, ports which don't call
stack_ctrl_init() are broken now (report RuntimeError on startup). Save
them trouble and just init stack control framework in interpreter init.

py/runtime.c

@@ -45,6 +45,7 @@
 #include "smallint.h"
 #include "objgenerator.h"
 #include "lexer.h"
+#include "stackctrl.h"
 
 #if 0 // print debugging info
 #define DEBUG_PRINT (1)
@@ -69,6 +70,8 @@ const mp_obj_module_t mp_module___main__ = {
 };
 
 void mp_init(void) {
+    stack_ctrl_init();
+
     // call port specific initialization if any
 #ifdef MICROPY_PORT_INIT_FUNC
     MICROPY_PORT_INIT_FUNC;

stmhal/main.c

@@ -187,7 +187,6 @@ static const char fresh_readme_txt[] =
 int main(void) {
     // TODO disable JTAG
 
-    stack_ctrl_init();
     // Stack limit should be less than real stack size, so we
     // had chance to recover from limit hit.
     stack_set_limit(&_ram_end - &_heap_end - 512);

unix/main.c

@@ -265,7 +265,6 @@ void pre_process_options(int argc, char **argv) {
 #endif
 
 int main(int argc, char **argv) {
-    stack_ctrl_init();
     stack_set_limit(32768);
 
     pre_process_options(argc, argv);