hardwared: gracefully handle no thermal readings

unclear if this is a hardware issue or not, but it crashes hardwared

`22b0b51eb1991fe6/00000003--cd41c126da`
```
[18.147382] MAIN 0 kernel - spmi spmi-0: pmic_arb_wait_for_done: transaction failed (0x3)
[18.147695] MAIN 0 kernel - qcom,qpnp-temp-alarm c440000.qcom,spmi:qcom,pm8005@4:qcom,temp-alarm@2400: qpnp_tm_read: regmap_bulk_readl failed. sid=4, addr=2408, len=1, rc=-5
```

temperature should probably be NaN or inf in the log, then everything downstream needs to handle those values