Can pl_Hold return NULL ?

p_sys cannot be null here.

This fix the big bug of disappearing of the interface in embedded mode.
(cherry picked from commit 29e96eae)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

(cherry picked from commit 95c17341)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

(cherry picked from commit cecdd2aa)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

(cherry picked from commit 6b67205f13b3f8ce5a3c860b63a95f3bccf8d934)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

It is more reactive and let decoder do proper late/early checks.

This does not work well. It seems that a high level of audio is buffered
inside aout after the input fifo (mixer or output one).