pcm: direct: Fix the missing appl_ptr update

pcm: direct: Fix the missing appl_ptr update

A snd_pcm_status() call for the direct plugins receives the status
from the slave PCM, but this doesn't contain a valid appl_ptr, since
the slave PCM for the direct plugins is in a free-wheel mode, hence
the appl_ptr is always zero.  This result in the inconsistent
status->appl_ptr and pcm->appl.ptr, hitting the recently introduced
assert() call.

Fix it by transferring the plugin's appl_ptr to the upper caller.

BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1181194
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>