ethtool: fix a build warning am: 63205d83b8 am: ce9e8b60ce am: 51bd9e9ff6 am: 195a5e4e97 am: 4935f0be0b

Original change: https://android-review.googlesource.com/c/platform/external/ethtool/+/2804535

Change-Id: Id3da2861747d78f9ca406fb0a2b03fc673fe2609
Signed-off-by: Automerger Merge Worker <[email protected]>