hwmon: (coretemp) Remove obsolete temp_data->valid

Checking for the valid bit of IA32_THERM_STATUS is removed in commit
bf6ea084 ("hwmon: (coretemp) Do not return -EAGAIN for low
temperatures"), and temp_data->valid is set and never cleared when the
temperature has been read once.

Remove the obsolete temp_data->valid field.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20221108075051.5139-2-rui.zhang@intel.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>