Remove max num threads in AIX build. Use MAX_NB_JOBS instead.

getarch.c

@@ -2006,13 +2006,8 @@ printf("ELF_VERSION=2\n");
   #endif
 #elif NO_PARALLEL_MAKE==1
     printf("MAKEFLAGS += -j 1\n");
-#else
-#ifdef _AIX
-    int count = get_num_cores();
-    printf("MAKEFLAGS += -j %d\n", (count > 32) ? 32 : count);
 #else
     printf("MAKEFLAGS += -j %d\n", get_num_cores());
-#endif
 #endif
 
     break;