[media] tea575x: convert to library

The module is used only as a library for now. Remove module init and exit
routines to show this.

While here, remove FSF snail address and attach EXPORT_SYMBOL() macros to
corresponding functions.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>