ALSA: hda - Replace hda_bus_ops with static binding

Originally hda_bus takes its own ops (hda_bus_ops) to allow different
controller drivers giving individual implementations of PCM
attachment, etc.  But this never happened and we finally merged both
codec and controller helper codes.  Thus there is no merit to keep the
indirect accesses to functions via hda_bus_ops.

This patch replaces these calls with the direct local function calls
for simplification.

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