Drivers: hv: util: Properly pack the data for file copy functionality

Properly pack the data for file copy functionality. Patch based on
investigation done by Matej Muzila <mmuzila@redhat.com>

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reported-by: <qge@redhat.com>
Cc: <stable@vger.kernel.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/hyperv.h

@@ -137,7 +137,7 @@ struct hv_do_fcopy {
 	__u64	offset;
 	__u32	size;
 	__u8	data[DATA_FRAGMENT];
-};
+} __attribute__((packed));
 
 /*
  * An implementation of HyperV key value pair (KVP) functionality for Linux.