pcm: ladspa: Delay LADSPA plugin activate call

Some LADSPA Plugins rely on connected control ports on activate call.
While this is not okay by spec, the spec also encourages the activate
call happening as late as possible.

Signed-off-by: Matthias Larisch <mail@matthias-larisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
pcm: rate: Don't return negative frame count on success in rewind

snd_pcm_rewind is documented to return <0 on failure and >=0 on
success.

Signed-off-by: Andrew Eikum <aeikum@codeweavers.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>