drm/i915/audio: add codec wakeup override enabled/disable callback

Add support for enabling codec wakeup override signal to allow
re-enumeration of the controller on SKL after resume from low power state.

In SKL, HDMI/DP codec and PCH HD Audio Controller are in different power
wells, so it's necessary to reset display audio codecs when power well on,
otherwise display audio codecs will disappear when resume from low power
state.
Reset steps when power on:
    enable codec wakeup -> azx_init_chip() -> disable codec wakeup

v3 by Jani: Simplify to only support toggling the appropriate chicken bit.

v4 by Han: add explanation and specify the hw swquence.

Signed-off-by: Lu, Han <han.lu@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Takashi Iwai <tiwai@suse.de>