cdc-acm: fix uninitialized variable

variable struct usb_cdc_parsed_header h may be used
uninitialized in acm_probe.

In kernel 4.8.

/* handle quirks deadly to normal probing*/
if (quirks == NO_UNION_NORMAL)

...

goto skip_normal_probe;
}

we bypass call to

cdc_parse_cdc_header(&h, intf, buffer, buflen);

but later use h in

if (h.usb_cdc_country_functional_desc) { /* export the country data */

Signed-off-by: Oliver Neukum <[e-mail]>
CC: [e-mail]
Reported-by: Victor Sologoubov <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/class/cdc-acm.c

···
 	if (quirks == IGNORE_DEVICE)
 		return -ENODEV;
 
+	memset(&h, 0x00, sizeof(struct usb_cdc_parsed_header));
+
 	num_rx_buf = (quirks == SINGLE_RX_URB) ? 1 : ACM_NR;
 
 	/* handle quirks deadly to normal probing*/