We need to check if any of the pipes is using TRANSCODER_EDP.

V2: DDI_BUF_CTL was renamed, so fix the usage here.
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>