Fix typos in comments of HEURISTIC2_LIMIT, NO_PTHREAD_TRYLOCK

(fix of commits acf2e57, 9a20535)

* include/private/gcconfig.h [POWERPC && SN_TARGET_PS3]
(NO_PTHREAD_TRYLOCK): Fix typo ("implementation uses") in comment.
* include/private/gcconfig.h [ALPHA && OSF1] (HEURISTIC2_LIMIT): Fix
typo ("bound") in comment.

include/private/gcconfig.h

@@ -1231,7 +1231,7 @@ EXTERN_C_BEGIN
 #     define STACKBOTTOM ((ptr_t)ps3_get_stack_bottom())
 #     define NO_PTHREAD_TRYLOCK
                 /* Current LOCK() implementation for PS3 explicitly     */
-                /* use pthread_mutex_lock for some reason.              */
+                /* uses pthread_mutex_lock for some reason.             */
 #   endif
 #   ifdef AIX
 #     define OS_TYPE "AIX"
@@ -1862,7 +1862,7 @@ EXTERN_C_BEGIN
 /* #define HEURISTIC2 */
         /* Normally HEURISTIC2 is too conservative, since               */
         /* the text segment immediately follows the stack.              */
-        /* Hence we give an upper pound.                                */
+        /* Hence we give an upper bound.                                */
         /* This is currently unused, since we disabled HEURISTIC2       */
         extern int __start[];
 #       define HEURISTIC2_LIMIT ((ptr_t)((word)(__start) \