What initially seemed to be a typo in fglrx (using register 0x740c
instead of 0x74dc) appeared to be a correct behavior. DCE3 has ACR and
CRC registers swapped which explains why we needed
WREG32(HDMI0_AUDIO_CRC_CONTROL + offset, 0x1000);

This has been tested for possible regressions on DCE3 HD3470 (RV620).
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>