x86: Fix object scope in the CPUID code.
x86: Fix object scope in the CPUID code.

The original version of the code takes a pointer from a temporary object
which gets destroyed before the pointer is used.

Change-Id: I16af4eefdf202f769a672e230330d8e0bfce3bb7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/37695
Reviewed-by: Matthew Poremba <f1eb50f3368ce197c52b19f7fdb5aa7a278f15fd@amd.com>
Reviewed-by: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>
Maintainer: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

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