Update some comments; Fix grammatic error in ChangeLog.

ChangeLog

@@ -11727,5 +11727,5 @@
 	  in all SAM DMA logic, unionfs, OS signalling logic,
 	* configs/nucleo-144: Basic port for the Nucleo-144 board with the
 	  STM32F746ZG MCU.  From Kconstantin Berezenko (2015-05-12).
-	* arch/arm-src/armv7-a:  Complete logic to initialize each CPUn, n > 0,
-	  when CONFIG_SMP=y (2016-05-13).
+	* arch/arm-src/armv7-a:  Complete re-design of logic to initialize each
+	  CPUn, n > 0, when CONFIG_SMP=y (2016-05-13).

arch/arm/src/armv7-a/arm_cpuidlestack.c

@@ -100,7 +100,7 @@ static FAR const uint32_t *g_cpu_stackalloc[CONFIG_SMP_NCPUS] =
  *      In this case, a new stack will need to be created for the IDLE
  *      thread and this function is then equivalent to:
  *
- *      up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
+ *      return up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
  *
  *   The following TCB fields must be initialized by this function:
  *

arch/sim/src/up_cpuidlestack.c

@@ -75,7 +75,7 @@
  *      In this case, a new stack will need to be created for the IDLE
  *      thread and this function is then equivalent to:
  *
- *      up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
+ *      return up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
  *
  *   The following TCB fields must be initialized by this function:
  *

include/nuttx/arch.h

@@ -1745,7 +1745,7 @@ int up_cpu_index(void);
  *      In this case, a new stack will need to be created for the IDLE
  *      thread and this function is then equivalent to:
  *
- *      up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
+ *      return up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
  *
  *   The following TCB fields must be initialized by this function:
  *