thermal/drivers/cpufreq_cooling: Use device name instead of auto-numbering

thermal/drivers/cpufreq_cooling: Use device name instead of auto-numbering

Currently the naming of a cooling device is just a cooling technique
followed by a number. When there are multiple cooling devices using
the same technique, it is impossible to clearly identify the related
device as this one is just a number.

For instance:

 thermal-cpufreq-0
 thermal-cpufreq-1
 etc ...

The 'thermal' prefix is redundant with the subsystem namespace. This
patch removes the 'thermal' prefix and changes the number by the device
name. So the naming above becomes:

 cpufreq-cpu0
 cpufreq-cpu4
 etc ...

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lore.kernel.org/r/20210314111333.16551-2-daniel.lezcano@linaro.org