[ALSA] sound - fix .iface field of mixer control elements

Documentation,CS46xx driver,EMU10K1/EMU10K2 driver,AD1848 driver
SB16/AWE driver,CMIPCI driver,ENS1370/1+ driver,RME32 driver
RME96 driver,ICE1712 driver,ICE1724 driver,KORG1212 driver
RME HDSP driver,RME9652 driver
This patch changes .iface to SNDRV_CTL_ELEM_IFACE_MIXER whre _PCM or
_HWDEP was used in controls that are not associated with a specific PCM
(sub)stream or hwdep device, and changes some controls that got
inconsitent .iface values due to copy+paste errors.  Furthermore, it
makes sure that all control that do use _PCM or _HWDEP use the correct
number in the .device field.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl

@@ -3422,10 +3422,17 @@ struct _snd_pcm_runtime {
 
       <para>
         The <structfield>iface</structfield> field specifies the type of
-      the control,
-      <constant>SNDRV_CTL_ELEM_IFACE_XXX</constant>. There are
-      <constant>MIXER</constant>, <constant>PCM</constant>,
-      <constant>CARD</constant>, etc.
+      the control, <constant>SNDRV_CTL_ELEM_IFACE_XXX</constant>, which
+      is usually <constant>MIXER</constant>.
+      Use <constant>CARD</constant> for global controls that are not
+      logically part of the mixer.
+      If the control is closely associated with some specific device on
+      the sound card, use <constant>HWDEP</constant>,
+      <constant>PCM</constant>, <constant>RAWMIDI</constant>,
+      <constant>TIMER</constant>, or <constant>SEQUENCER</constant>, and
+      specify the device number with the
+      <structfield>device</structfield> and
+      <structfield>subdevice</structfield> fields.
       </para>
 
       <para>