ACPI: processor_driver: add missing kfree

The function acpi_processor_add is stored in the ops.add field of a
acpi_driver structure.  This function is then called in
acpi_bus_driver_init.  On failure, this function clears the field
device->driver_data, but does not free its contents.  Thus the free has to
be done by the add function.  In acpi_processor_add, the corresponding
value is pr.  This value is currently freed on failure before storing it in
device->driver_data, but not after.  This free is added in the error
handling code at the end of the function.  The per_cpu variable
processors is also cleared so that it does not refer to a dangling pointer.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>