Voice Prompts always reports "on", and the language only decodes when prompts are on

On a QC35 (firmware 3.0.3) the status output is wrong in two ways that share one cause:
- VP_MASK is 0x7f and is used both to strip flag bits before the language lookup and to test the voice-prompt flag.
- The prompt-language byte is 0x81 with prompts off and 0xa1 with prompts on, they differ by exactly 0x20, so that bit is the flag, and 0x80 is new in 3.x.

Masking with 0x7f makes the flag test true for any non-zero byte, and leaves the language undecoded when prompts are off, since every PL_* constant carries 0x20.

```
prompts on Language: EN Voice Prompts: on
prompts off Language: Unknown [0x81] Voice Prompts: on ← both wrong
```
I have a patch and can open a PR.