When maxcpus=X kernel argument is used, we parse the ACPI tables only
for the first X cpus. The per-cpu ACPI data include the _PSD tables
which gives information about related cpus.

cppc_cpufreq and acpi-cpufreq parses the table once during init to
deduce the related cpus. If a user brings a new cpu online after boot
the related cpu data becomes incorrect.

acpi_get_psd_map() in acpi_cppc.c returns error if it fails to find
the parsed ACPI data for possible CPU resulting in cppc_cpufreq
initialization failure.

With this change we will probe all possible CPUs prior to cpufreq
initialization, but will bring only setup_max_cpus online. nr_cpus
kernel parameter can be used to restict even parsing per-cpu ACPI
tables.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>