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

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