Fix example-fsm-55 and documentation.

example-fsm-55/Makefile

@@ -25,7 +25,7 @@ OBJCOPY   = $(CROSS)objcopy
 MCU   = cortex-m0 # -save-temps
 CWARN = -Wall -Wextra -Wstrict-prototypes
 DEFS  = -DMAKE_ENTRY_PUBLIC \
-        -DFREE_STANDING -DMHZ=48 -DUSE_WFI_FOR_IDLE
+        -DFREE_STANDING -DMHZ=48
 OPT   = -O3 -Os -g
 LIBS  =
 

example-fsm-55/hh.c

@@ -366,6 +366,8 @@ main (int argc, const char *argv[])
   (void)argc;
   (void)argv;
 
+  chopstx_conf_idle (1);
+
   chopstx_mutex_init (&mtx);
   chopstx_cond_init (&cnd0);
   chopstx_cond_init (&cnd1);