tty: tty_io.c shadows sparse fix

drivers/char/tty_io.c:1413:17: warning: symbol 'buf' shadows an earlier one
drivers/char/tty_io.c:1379:20: originally declared here
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/tty_io.c

@@ -1026,19 +1026,19 @@ static inline ssize_t do_tty_write(
 
 	/* write_buf/write_cnt is protected by the atomic_write_lock mutex */
 	if (tty->write_cnt < chunk) {
-		unsigned char *buf;
+		unsigned char *buf_chunk;
 
 		if (chunk < 1024)
 			chunk = 1024;
 
-		buf = kmalloc(chunk, GFP_KERNEL);
-		if (!buf) {
+		buf_chunk = kmalloc(chunk, GFP_KERNEL);
+		if (!buf_chunk) {
 			ret = -ENOMEM;
 			goto out;
 		}
 		kfree(tty->write_buf);
 		tty->write_cnt = chunk;
-		tty->write_buf = buf;
+		tty->write_buf = buf_chunk;
 	}
 
 	/* Do the write .. */