ALSA: compress: Pass through return value of open ops callback

The snd_compr_open function would always return 0 even if the compressed
ops open function failed, obviously this is incorrect. Looks like this
was introduced by a small typo in:

commit a0830dbd


ALSA: Add a reference counter to card instance

This patch returns the value from the compressed op as it should.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>