utils: raspberrypi: ctt: Fix pycodestyle E302

E302 expected 2 blank lines, found 0

Note that issues are still flagged, due to the use of docstrings as
multi-lines comments. This will be addressed separately.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>

utils/raspberrypi/ctt/ctt_awb.py

@@ -9,6 +9,7 @@ import matplotlib.pyplot as plt
 from bisect import bisect_left
 from scipy.optimize import fmin
 
+
 """
 obtain piecewise linear approximation for colour curve
 """