[media] tvaudio: add back lost tda9875 copyright

When the separate tda9875 driver was merged into tvaudio the copyright
line of the tda9875 driver was dropped inadvertently. Add it back.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/i2c/tvaudio.c

@@ -7,6 +7,10 @@
  *   Steve VanDeBogart (vandebo@uclink.berkeley.edu)
  *   Greg Alexander (galexand@acm.org)
  *
+ * For the TDA9875 part:
+ * Copyright (c) 2000 Guillaume Delvit based on Gerd Knorr source
+ * and Eric Sandeen
+ *
  * Copyright(c) 2005-2008 Mauro Carvalho Chehab
  *	- Some cleanups, code fixes, etc
  *	- Convert it to V4L2 API