drm/i915: hsw+ audio regs are per-transocder

s/pipe/transcoder/ when dealing with hsw+ audio registers. This
won't actually make any real difference since there is no audio
on the EDP transcoder. But this should avoid a bit of confusion
when cross checking against the spec.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190430142901.7302-2-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>