dt-bindings: net/nfc: ti,trf7970a: Add ti,rx-gain-reduction-db option

Add option to reduce the RX antenna gain to be able to reduce the
sensitivity.

Signed-off-by: Paul Geurts <paul.geurts@prodrive-technologies.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250626141242.3749958-2-paul.geurts@prodrive-technologies.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: paulgeurts

Documentation/devicetree/bindings/net/nfc/ti,trf7970a.yaml

@@ -55,6 +55,12 @@ properties:
     description: |
       Regulator for supply voltage to VIN pin
 
+  ti,rx-gain-reduction-db:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Specify an RX gain reduction to reduce antenna sensitivity with 5dB per
+      increment, with a maximum of 15dB. Supported values: [0, 5, 10, 15].
+
 required:
   - compatible
   - interrupts
@@ -95,5 +101,6 @@ examples:
             irq-status-read-quirk;
             en2-rf-quirk;
             clock-frequency = <27120000>;
+            ti,rx-gain-reduction-db = <15>;
         };
     };