perf/x86/intel: Factor out the initialization code for SPR

The SPR and ADL p-core have a similar uarch. Most of the initialization
code can be shared.

Factor out intel_pmu_init_glc() for the common initialization code.
The common part of the ADL p-core will be replaced by the later patch.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230829125806.3016082-3-kan.liang@linux.intel.com