selftests: net: devlink_port_split: check devlink returned an element before dereferencing it
And thus avoid a Python stacktrace:
~/linux/tools/testing/selftests/net$ ./devlink_port_split.py
Traceback (most recent call last):
File "/home/linux/tools/testing/selftests/net/./devlink_port_split.py",
line 277, in <module> main()
File "/home/linux/tools/testing/selftests/net/./devlink_port_split.py",
line 242, in main
dev = list(devs.keys())[0]
IndexError: list index out of range
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>