power: Replace LenovoWmiTdpLimiter with FirmwareAttributeTdpLimiter

It seems several devices use a firmware-attribute interface to do TDP limiting.
This turns LenovoWmiTdpLimiter into a generic interface that can be configured
to use an arbitrary firmware-attribute name and check for an arbitrary power
profile.

src/manager/user.rs

@@ -1026,6 +1026,7 @@ mod test {
                 method: TdpLimitingMethod::GpuHwmon,
                 range: Some(RangeConfig::new(3, 15)),
                 download_mode_limit: NonZeroU32::new(6),
+                firmware_attribute: None,
             }),
             gpu_clocks: Some(RangeConfig::new(200, 1600)),
             battery_charge_limit: Some(BatteryChargeLimitConfig {