hwmon: (coretemp) Remove bogus __cpuinitdata etc cleanup

The CPU hotplug notifier_block coretemp_cpu_notifier is already defined
inside an #ifdef HOTPLUG_CPU, therefore marking it as __cpuinitdata is
quite a pointless thing to do.

Also, remove duplicate prototype of function coretemp_update_device()
at the top of this file (another one already exists barely 10 lines
above this one :-)

Signed-off-by: Satyam Sharma <satyam@infradead.org>
Acked-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>