dt-bindings: power: supply: sc27xx-fg: document deprecated bat-detect-gpio

While the bindings have always used the correct 'battery-detect-gpios'
property, the DTS and the Linux driver have been using the incorrect
'bat-detect-gpio' property. Document this property and mark it
as deprecated.

Signed-off-by: Stanislav Jakubek <stano.jakubek@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lore.kernel.org/r/f334c973dd4e6390a0cd51dbde358277a07604d7.1730720720.git.stano.jakubek@gmail.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Author: Stanislav Jakubek

Documentation/devicetree/bindings/power/supply/sc27xx-fg.yaml

@@ -27,6 +27,11 @@ properties:
   battery-detect-gpios:
     maxItems: 1
 
+  bat-detect-gpio:
+    maxItems: 1
+    deprecated: true
+    description: use battery-detect-gpios instead
+
   interrupts:
     maxItems: 1