unix: skip ethtool driver test for busy interface

This CL skips IoctlGetEthtoolDrvinfo on busy interface tests since
ethtool getting the same result too.

Fixes golang/go#67350

Change-Id: Ia65678e3caab8a9dd42b9cdb8e4cb7f7f0b476da
Reviewed-on: https://go-review.googlesource.com/c/sys/+/586435
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

unix/syscall_linux_test.go

@@ -54,6 +54,12 @@ func TestIoctlGetEthtoolDrvinfo(t *testing.T) {
 				continue
 			}
 
+			if err == unix.EBUSY {
+				// See https://go.dev/issues/67350
+				t.Logf("%s: ethtool driver busy, possible kernel bug", ifi.Name)
+				continue
+			}
+
 			t.Fatalf("failed to get ethtool driver info for %q: %v", ifi.Name, err)
 		}