hwmon: (coretemp) Fix bogus core_id to attr name mapping

[ Upstream commit fdaf0c86 ]

Before commit 7108b80a ("hwmon/coretemp: Handle large core ID
value"), there is a fixed mapping between
1. cpu_core_id
2. the index in pdata->core_data[] array
3. the sysfs attr name, aka "tempX_"
The later two always equal cpu_core_id + 2.

After the commit, pdata->core_data[] index is got from ida so that it
can handle sparse core ids and support more cores within a package.

However, the commit erroneously maps the sysfs attr name to
pdata->core_data[] index instead of cpu_core_id + 2.

As a result, the code is not aligned with the comments, and brings user
visible changes in hwmon sysfs on systems with sparse core id.

For example, before commit 7108b80a ("hwmon/coretemp: Handle large
core ID value"),
/sys/class/hwmon/hwmon2/temp2_label:Core 0
/sys/class/hwmon/hwmon2/temp3_label:Core 1
/sys/class/hwmon/hwmon2/temp4_label:Core 2
/sys/class/hwmon/hwmon2/temp5_label:Core 3
/sys/class/hwmon/hwmon2/temp6_label:Core 4
/sys/class/hwmon/hwmon3/temp10_label:Core 8
/sys/class/hwmon/hwmon3/temp11_label:Core 9
after commit,
/sys/class/hwmon/hwmon2/temp2_label:Core 0
/sys/class/hwmon/hwmon2/temp3_label:Core 1
/sys/class/hwmon/hwmon2/temp4_label:Core 2
/sys/class/hwmon/hwmon2/temp5_label:Core 3
/sys/class/hwmon/hwmon2/temp6_label:Core 4
/sys/class/hwmon/hwmon2/temp7_label:Core 8
/sys/class/hwmon/hwmon2/temp8_label:Core 9

Restore the previous behavior and rework the code, comments and variable
names to avoid future confusions.

Fixes: 7108b80a

 ("hwmon/coretemp: Handle large core ID value")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-3-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>