Update rpi.md to clarify watchdog setup instructions  (#295)
Update rpi.md to clarify watchdog setup instructions  (#295)

* remove Disabling password login section as it's confusing to new users

* Update rpi.md to clarify watchdog setup instructions

before:
```
max-load-1
watchdog-device
```

but the actual file looks more like:
```
max-load-1              = 24
watchdog-device         = /dev/watchdog
```

Jieseldeep/docs,dakago/docs,Pazoles/docs,danamlewis/docs,danamlewis/docs,jbwittmer/docs,sarahspins/docs,openaps/docs