x86/intel: distinguish LP-Ecore using native model id

[bgoglin]

Linux commit 9f4a39757c81d532f64232702537c53ad4092a5e says:
"The upcoming ARL-H hybrid processor contains 2 different atom uarchs which have different PMU capabilities. To distinguish these atom uarchs, CPUID.1AH.EAX[23:0] defines a native model ID which can be used to uniquely identify the uarch of the core by combining with core type."

We currently only look at the core type field to distinguish Atom and Core. We should use the native model ID to further distinguish between Ecore and LP-ECore. Right now, skymont (model 3 = next Ecore) is considered normal while crestmont (model 2 = current Ecore) is LP. Not sure if we should just hardwire that 3 = Atom and 2 = LP or if there's any way to generalize this.

Linux 6.13 (and hwloc 2.12) will expose the difference in PMU sets. We'll get both CoreType=IntelAtom (from x86) and CoreType=IntelLowPower (from Linux) on those LP Ecores.