[PATCH] USB: usb_cdc build fix

With older gcc's:

In file included from drivers/usb/class/cdc-acm.c:63:
include/linux/usb_cdc.h:117: field `bDetailData' has incomplete type
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

diff -puN include/linux/usb_cdc.h~usb_cdc-build-fix include/linux/usb_cdc.h

include/linux/usb_cdc.h

@@ -114,7 +114,7 @@ struct usb_cdc_mdlm_detail_desc {
 
 	/* type is associated with mdlm_desc.bGUID */
 	__u8	bGuidDescriptorType;
-	__u8	bDetailData[];
+	__u8	bDetailData[0];
 } __attribute__ ((packed));
 
 /*-------------------------------------------------------------------------*/