dynamic_debug: small cleanup in ddebug_proc_write()

This doesn't change behavior at all.  In the original code, if nwords was
zero then ddebug_parse_query() would return -EINVAL, now we just do it
earlier.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/dynamic_debug.c

@@ -456,7 +456,7 @@ static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
 			__func__, (int)len);
 
 	nwords = ddebug_tokenize(tmpbuf, words, MAXWORDS);
-	if (nwords < 0)
+	if (nwords <= 0)
 		return -EINVAL;
 	if (ddebug_parse_query(words, nwords-1, &query))
 		return -EINVAL;