ALSA: ctxfi - Clear PCM resources at hw_params and hw_free

Currently the PCM resources are allocated only once and ever in prepare
callback, assuming that the PCM parameters are never changed.  But it's
not true.

This patch adds the call of atc->pcm_release_resources() at hw_params
and hw_free callbacks to assure that the PCM setup is done correctly
for each h/w parameter changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>