drivers/net/irda/irda-usb.c: fix buffer overflow

Taken from http://bugzilla.kernel.org/show_bug.cgi?id=12397

We're doing an sprintf of an 11-char string into an 11-char buffer. 
Whoops.  It breaks firmware uploading.
Reported-by: NJos-Vicente Gilabert <josevteg@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/irda/irda-usb.c

@@ -1073,7 +1073,7 @@ static int stir421x_patch_device(struct irda_usb_cb *self)
 {
 	unsigned int i;
 	int ret;
-	char stir421x_fw_name[11];
+	char stir421x_fw_name[12];
 	const struct firmware *fw;
 	const unsigned char *fw_version_ptr; /* pointer to version string */
 	unsigned long fw_version = 0;