platform/x86/intel/pmt: Use PMT callbacks

PMT providers may require device specific actions before their telemetry
may be read. If the read_telem() is assigned, call it instead of
memcpy_fromio() and return. Since this needs to be done in multiple
locations, add pmt_telem_read_mmio() as a wrapper function to perform this
and any other needed checks.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20240725122346.4063913-4-michael.j.ruhl@intel.com


Signed-off-by: Hans de Goede <hdegoede@redhat.com>