dt-bindings: spmi: Deprecate qcom,bus-id

As it is optional and no platform is actually using the secondary bus,
deprecate the qcom,bus-id property. For newer platforms that implement
SPMI PMIC ARB v7 in HW, the X1E80100 approach should be used.

Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Abel Vesa <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/spmi/qcom,spmi-pmic-arb.yaml

···
     description: >
       SPMI bus instance. only applicable to PMIC arbiter version 7 and beyond.
       Supported values, 0 = primary bus, 1 = secondary bus
+    deprecated: true
 
 required:
   - compatible