mfd: arizona: Remove audio bindings from MFD binding document

Now the audio bindings have their own binding document update the main
MFD document to point to that file and remove the audio binding
documentation.

Signed-off-by: Charles Keepax <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/mfd/arizona.txt

···
     a value that is out of range for a 16 bit register then the chip default
     will be used. If present exactly five values must be specified.
 
-  - wlf,inmode : A list of INn_MODE register values, where n is the number
-    of input signals. Valid values are 0 (Differential), 1 (Single-ended) and
-    2 (Digital Microphone). If absent, INn_MODE registers set to 0 by default.
-    If present, values must be specified less than or equal to the number of
-    input signals. If values less than the number of input signals, elements
-    that have not been specified are set to 0 by default. Entries are:
-    <IN1, IN2, IN3, IN4> (wm5102, wm5110, wm8280, wm8997)
-    <IN1A, IN2A, IN1B, IN2B> (wm8998, wm1814)
-  - wlf,out-mono : A list of boolean values indicating whether each output is
-    mono or stereo. Position within the list indicates the output affected
-    (eg. First entry in the list corresponds to output 1). A non-zero value
-    indicates a mono output. If present, the number of values should be less
-    than or equal to the number of outputs, if less values are supplied the
-    additional outputs will be treated as stereo.
-
-  - wlf,dmic-ref : DMIC reference voltage source for each input, can be
-    selected from either MICVDD or one of the MICBIAS's, defines
-    (ARIZONA_DMIC_xxxx) are provided in <dt-bindings/mfd/arizona.txt>. If
-    present, the number of values should be less than or equal to the
-    number of inputs, unspecified inputs will use the chip default.
-
-  - wlf,max-channels-clocked : The maximum number of channels to be clocked on
-    each AIF, useful for I2S systems with multiple data lines being mastered.
-    Specify one cell for each AIF to be configured, specify zero for AIFs that
-    should be handled normally.
-    If present, number of cells must be less than or equal to the number of
-    AIFs. If less than the number of AIFs, for cells that have not been
-    specified the corresponding AIFs will be treated as default setting.
-
-  - wlf,spk-fmt : PDM speaker data format, must contain 2 cells (OUT5 and OUT6).
-    See the datasheet for values.
-    The second cell is ignored for codecs that do not have OUT6 (wm5102, wm8997,
-      wm8998, wm1814)
-
-  - wlf,spk-mute : PDM speaker mute setting, must contain 2 cells (OUT5 and OUT6).
-    See the datasheet for values.
-    The second cell is ignored for codecs that do not have OUT6 (wm5102, wm8997,
-    wm8998, wm1814)
-
   - DCVDD-supply, MICVDD-supply : Power supplies, only need to be specified if
     they are being externally supplied. As covered in
     Documentation/devicetree/bindings/regulator/regulator.txt
···
 Also see child specific device properties:
   Regulator - ../regulator/arizona-regulator.txt
   Extcon    - ../extcon/extcon-arizona.txt
+  Sound     - ../sound/arizona.txt
 
 Example: