dt-bindings: i2c: realtek,rtl9301-i2c: fix wording and typos

Fix wording of binding description to use plural because there is not
only a single RTL9300 SoC. RTL9300 describes a whole family of Realtek
SoCs.

Add missing word 'of' in description of reg property.

Change 'SDA pin' to 'SDA line number' because the property must contain
the SDA (channel) number ranging from 0-7 instead of a real pin number.

Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Tested-by: Chris Packham <chris.packham@alliedtelesis.co.nz> # On RTL9302C based board
Tested-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250927101931.71575-3-jelonek.jonas@gmail.com

Author: jonasjelonek

Documentation/devicetree/bindings/i2c/realtek,rtl9301-i2c.yaml

@@ -10,7 +10,7 @@ maintainers:
   - Chris Packham <chris.packham@alliedtelesis.co.nz>
 
 description:
-  The RTL9300 SoC has two I2C controllers. Each of these has an SCL line (which
+  RTL9300 SoCs have two I2C controllers. Each of these has an SCL line (which
   if not-used for SCL can be a GPIO). There are 8 common SDA lines that can be
   assigned to either I2C controller.
 
@@ -27,7 +27,7 @@ properties:
 
   reg:
     items:
-      - description: Register offset and size this I2C controller.
+      - description: Register offset and size of this I2C controller.
 
   "#address-cells":
     const: 1
@@ -42,7 +42,7 @@ patternProperties:
 
     properties:
       reg:
-        description: The SDA pin associated with the I2C bus.
+        description: The SDA line number associated with the I2C bus.
         maxItems: 1
 
     required: