hwmon: (coretemp) Replace x86_model checks with VFM ones

hwmon: (coretemp) Replace x86_model checks with VFM ones

Intel CPUs have been using Family 6 for a while. The Family-model checks
in the coretemp driver implicitly assume Family 6. With the upcoming
Family 18 and 19 models, some of these checks fall apart.

While reading the temperature target MSR, cpu_has_tjmax() performs model
checks only to determine if a device warning should be printed. Instead
of expanding the checks, get rid of the function and print the warning
once unconditionally if the MSR read fails. The checks aren't worth
preventing a single line warning to dmesg.

Update the rest of the x86_model checks with VFM ones to make them more
robust. This automatically covers the upcoming Family 18 and 19 as well
as any future extended families.

Add a code comment to reflect that none of the CPUs in Family 5 or
Family 15 set X86_FEATURE_DTHERM. The VFM checks do not impact these
CPUs since the driver does not load on them.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250828201729.1145420-1-sohil.mehta@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>