Broke the sound output via HDMI

[Alex V. Petrov]

Broke the sound output via HDMI. A few days ago.

FreeBSD alex.super 10.1-PRERELEASE FreeBSD 10.1-PRERELEASE #10 r271013: 
Wed Sep  3 18:26:57 KRAT 2014 alex at alex.super:/usr/obj/usr/src/sys/ALEX  
amd64

cat /dev/sndstat
Installed devices:
pcm0: <NVIDIA (0x0016) (HDMI/DP 8ch)> (play)
pcm1: <NVIDIA (0x0016) (HDMI/DP 8ch)> (play)
pcm2: <NVIDIA (0x0016) (HDMI/DP 8ch)> (play)
pcm3: <NVIDIA (0x0016) (HDMI/DP 8ch)> (play)
pcm4: <Realtek ALC888 (Rear Analog 7.1/2.0)> (play/rec) default
pcm5: <Realtek ALC888 (Front Analog)> (play/rec)
pcm6: <Realtek ALC888 (Rear Digital)> (play/rec)

ls /dev/dsp*
/dev/dsp0.1
/dev/dsp1.0
/dev/dsp2.1
/dev/dsp3.1
/dev/dsp4.0
/dev/dsp5.0
/dev/dsp6.0

cat somefile > /dev/dsp??? worked only with /dev/dsp4.0 (pcm4: <Realtek 
ALC888 (Rear Analog 7.1/2.0)> (play/rec) default)