fix Undefined variable 'p'

Looking at check.sh

```
************* Module upconvert.parser.altium
W0622:102,12:Altium.parse: Redefining built-in 'input'
E0602:145,39:Altium.parse: Undefined variable 'p'
E0602:147,32:Altium.parse: Undefined variable 'p'
```

Am going to start going through more of errors, lemme know if someone is already handling before I pull request the wheel.