rtos: remove config.h includes from stackings headers

And add its own header to the rtos_xxx_stackings.c

Signed-off-by: Erhan Kurubas <erhan.kurubas@espressif.com>
Change-Id: I084130fde7ee8645129a7cf60bb7bf59448e2f39
Reviewed-on: https://review.openocd.org/c/openocd/+/7441
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

src/rtos/rtos_riot_stackings.c

@@ -12,6 +12,7 @@
 #include "rtos.h"
 #include "target/armv7m.h"
 #include "rtos_standard_stackings.h"
+#include "rtos_riot_stackings.h"
 
 /* This works for the M0 and M34 stackings as xPSR is in a fixed
  * location