hwmon: (coretemp) Further relax temperature range checks

Further relax temperature range checks after reading the IA32_TEMPERATURE_TARGET
register. If the register returns a value other than 0 in bits 16..32, assume
that the returned value is correct.

This change applies to both packet and core temperature limits.

Cc: Carsten Emde <C.Emde@osadl.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Fenghua Yu <fenghua.yu@intel.com>