uapi: cdc.h: cleanly provide for more interfaces and countries

The spec requires at least one interface respectively country.
It allows multiple ones. This needs to be clearly said in the UAPI.
This is subject to sanity checking in cdc_parse_cdc_header(), thus
we can trust the length.

Signed-off-by: Oliver Neukum <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/class/cdc-acm.c

···
 		if (!acm->country_codes)
 			goto skip_countries;
 		acm->country_code_size = cfd->bLength - 4;
-		memcpy(acm->country_codes, (u8 *)&cfd->wCountyCode0,
+		memcpy(acm->country_codes, cfd->wCountryCodes,
 							cfd->bLength - 4);
 		acm->country_rel_date = cfd->iCountryCodeRelDate;
 

include/uapi/linux/usb/cdc.h

···
 	__u8	bDescriptorSubType;
 
 	__u8	bMasterInterface0;
-	__u8	bSlaveInterface0;
-	/* ... and there could be other slave interfaces */
+	union {
+		__u8	bSlaveInterface0;
+		__DECLARE_FLEX_ARRAY(__u8, bSlaveInterfaces);
+	};
 } __attribute__ ((packed));
 
 /* "Country Selection Functional Descriptor" from CDC spec 5.2.3.9 */
···
 	__u8	bDescriptorSubType;
 
 	__u8	iCountryCodeRelDate;
-	__le16	wCountyCode0;
-	/* ... and there can be a lot of country codes */
+	union {
+		__le16	wCountryCode0;
+		__DECLARE_FLEX_ARRAY(__le16, wCountryCodes);
+	};
 } __attribute__ ((packed));
 
 /* "Network Channel Terminal Functional Descriptor" from CDC spec 5.2.3.11 */