CPU0/package0 is always online and the MMIO RAPL driver runs on single
package systems only, so there is no need to handle CPU hotplug in it.

Always register a RAPL package device for package 0 and remove the
unnecessary CPU hotplug support.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20240930081801.28502-6-rui.zhang@intel.com
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>