mediatek: fiilogic: device tree `switch@1f` fix

Quite a few `fiilogic` devices use the `mt7531` switch.
Some of them have a DT node that looks like:
```
switch: switch@0 {
	compatible = "mediatek,mt7531";
	reg = <31>;
...
};
```
This commit changes the DT node name to `switch@1f`.

Signed-off-by: Rani Hod <rani.hod@gmail.com>
(cherry picked from commit aaeb379023daf9720303884f61748fe362b0a237)