ALSA: hda: Remove substream allocation/free ops

ALSA: hda: Remove substream allocation/free ops

Since we dropped the memory page fiddling in the own allocators in
hda_intel.c, the substream allocation and free ops in both hda_intel.c
and hda_tegra.c became nothing but the simple calls of the standard
snd_pcm_lib helpers.  As both are identical, there is no longer need
for indirect calls via ops; it's a good opportunity for removing ops
and simplifying the codes.

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