Fixes the following warnings:

../utilities/checkpatch.py:219:1: E302 expected 2 blank lines, found 1
../utilities/checkpatch.py:224:1: E302 expected 2 blank lines, found 1
../utilities/checkpatch.py:228:1: E302 expected 2 blank lines, found 1

CC: Justin Pettit <jpettit@ovn.org>
Fixes: 4e99b70d

 ("checkpatch.py: Add check for "xxx" in comments.")
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>