USB: ftdi_sio: Quiet sparse noise about using plain integer was NULL pointer

commit a816e3113b63753c330ca4751ea1d208e93e3015 upstream.

Pointers should not be compared to plain integers.
Quiets the sparse warning:
warning: Using plain integer as NULL pointer

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Cc: Lotfi Manseur <lotfi.manseur@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index c6f8e62..f8a9cd7 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -2173,7 +2173,7 @@
 
 	cflag = termios->c_cflag;
 
-	if (old_termios == 0)
+	if (!old_termios)
 		goto no_skip;
 
 	if (old_termios->c_cflag == termios->c_cflag