filelist/modules: don't print "skipping..." when dir not found

I think this was still causing some confusion, since it *might* look
like a failure when in reality it's not. I think it's important that
mkinitfs prints when it is adding something, and doesn't print when it
is *not* adding something, so that it should be clear if something
expected is missing and when something unexpected is included... without
having to sort out which is which every time the output is read.

internal/filelist/modules/modules.go

@@ -70,7 +70,6 @@ func (m *Modules) List() (*filelist.FileList, error) {
 	log.Printf("- Searching for kernel modules from %s", m.modulesListPath)
 	fileInfo, err := os.ReadDir(m.modulesListPath)
 	if err != nil {
-		log.Println("-- Unable to find dir, skipping...")
 		return files, nil
 	}
 	for _, file := range fileInfo {