ALSA: seq: oss: fix typo

Fix typo in "announcement".

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/20220313085635.102123-1-Julia.Lawall@inria.fr


Signed-off-by: Takashi Iwai <tiwai@suse.de>