powercap: intel_rapl: Move primitive info to header for interface drivers

powercap: intel_rapl: Move primitive info to header for interface drivers

RAPL primitive information varies across different RAPL interfaces
(MSR, TPMI, MMIO). Keeping them in the common code adds no benefit, but
requires interface-specific handling logic and makes the common layer
unnecessarily complex.

Move the primitive info infrastructure to the shared header to allow
interface drivers to configure RAPL primitives. Specific changes:

 1. Move struct rapl_primitive_info, enum unit_type, and
    PRIMITIVE_INFO_INIT macro to intel_rapl.h.
 2. Change the @rpi field in struct rapl_if_priv from void * to
    struct rapl_primitive_info * to improve type safety and eliminate
    unnecessary casts.

No functional changes. This is a preparatory refactoring to allow
interface drivers to supply their own RAPL primitive settings.

Co-developed-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://patch.msgid.link/20260331211950.3329932-4-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>