stress-cpu: add LIKELY/UNLIKELY hints for stress_continue_flag

Signed-off-by: Colin Ian King <[email protected]>

stress-cpu.c

@@ -758,7 +758,7 @@ PRAGMA_UNROLL_N(8)
 					return EXIT_FAILURE;
 				}
 			}
-			if (!stress_continue_flag())
+			if (UNLIKELY(!stress_continue_flag()))
 				return EXIT_SUCCESS;
 		}
 	}