ALSA: hda/via - Add beep controls to VIA codecs

My codec has a beep-generating node:

  $ cat /proc/asound/card1/codec#0
  Codec: VIA VT1802
  ...
  Vendor Id: 0x11068446
  Subsystem Id: 0x15587410
  Revision Id: 0x100000
  ...
  Node 0x22 [Beep Generator Widget] wcaps 0x70040c: Mono Amp-Out
    Amp-Out caps: ofs=0x0a, nsteps=0x12, stepsize=0x05, mute=1
    Amp-Out vals:  [0x0a]
    Power states:  D0 D1 D2 D3
    Power: setting=D0, actual=D0
  ...

But I was missing the:

  Control: name=...

entries that I need to manage this widget from alsamixer.  With this
patch (based on the similar Mono Amp-Out handling in
patch_conexant.c), I get a new:

  input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:1b.0/sound/card1/hdaudioC1D0/input15

entry in dmesg and controls to manage that beep:

  $ cat /proc/asound/card1/codec#0 | grep -A5 Beep
  Node 0x22 [Beep Generator Widget] wcaps 0x70040c: Mono Amp-Out
    Control: name="Beep Playback Volume", index=0, device=0
      ControlAmp: chs=1, dir=Out, idx=0, ofs=0
    Control: name="Beep Playback Switch", index=0, device=0
      ControlAmp: chs=1, dir=Out, idx=0, ofs=0
    Amp-Out caps: ofs=0x0a, nsteps=0x12, stepsize=0x05, mute=1
    Amp-Out vals:  [0x12]
    Power states:  D0 D1 D2 D3
    Power: setting=D0, actual=D0

[rebased and modified for the latest tree by tiwai]

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Takashi Iwai <tiwai@suse.de>