module: remove use of uninitialized variable len

clang build reports
kernel/module/stats.c:307:34: error: variable
  'len' is uninitialized when used here [-Werror,-Wuninitialized]
        len = scnprintf(buf + 0, size - len,
                                        ^~~
At the start of this sequence, neither the '+ 0', nor the '- len' are needed.
So remove them and fix using 'len' uninitalized.

Fixes: df3e764d ("module: add debug stats to help identify memory pressure")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

kernel/module/stats.c

@@ -302,7 +302,7 @@ static ssize_t read_file_mod_stats(struct file *file, char __user *user_buf,
 		return -ENOMEM;
 
 	/* The beginning of our debug preamble */
-	len = scnprintf(buf + 0, size - len, "%25s\t%u\n", "Mods ever loaded", live_mod_count);
+	len = scnprintf(buf, size, "%25s\t%u\n", "Mods ever loaded", live_mod_count);
 
 	len += scnprintf(buf + len, size - len, "%25s\t%u\n", "Mods failed on kread", fkreads);