drivers/hwmon/coretemp.c: get TjMax value from MSR

The MSR IA32_TEMPERATURE_TARGET contains the TjMax value in the newer
Intel processors.

Signed-off-by: Huaxu Wan <huaxu.wan@linux.intel.com>
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Yong Wang <yong.y.wang@linux.intel.com>
Cc: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>