Fix syntax error in FFTW check

Author: ajocksch

cscs-checks/microbenchmarks/fft/fftw_benchmark.py

@@ -59,7 +59,7 @@ def __init__(self, exec_mode):
                 },
                 'kesch:cn': {
                     'fftw_exec_time': (1.58, None, 0.50, 's'),
-                }
+                },
                 '*': {
                     'fftw_exec_time': (0, None, None, 's'),
                 }