dt-bindings: hwmon: lm75: remove gmt,g751 from trivial devices

gmt,g751 is covered by LM75 sensor bindings.  This fixes warning:

  arch/arm/boot/dts/gemini-dlink-dns-313.dt.yaml: temperature-sensor@48:
    '#thermal-sensor-cells' does not match any of the regexes: 'pinctrl-[0-9]+'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210920182114.339419-2-krzysztof.kozlowski@canonical.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>