[media] sony-btf-mpx: Drop needless newline in param description

Module parameter descriptions need not be terminated with a newline.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>