V4L/DVB (4310): Saa7134: rename dmasound_{init, exit}

Two different exports with the same name are not a good idea:
$ grep -r EXPORT_SYMBOL\(dmasound_init\) *
drivers/media/video/saa7134/saa7134-core.c:EXPORT_SYMBOL(dmasound_init);
sound/oss/dmasound/dmasound_core.c:EXPORT_SYMBOL(dmasound_init);
$ 
This patch renames the saa7134 dmasound_{init,exit} to 
saa7134_dmasound_{init,exit}.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>