perf/x86/intel: Factor out the initialization code for ADL e-core

From PMU's perspective, the ADL e-core and newer SRF/GRR have a similar
uarch. Most of the initialization code can be shared.

Factor out intel_pmu_init_grt() for the common initialization code.
The common part of the ADL e-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/20230829125806.3016082-4-kan.liang@linux.intel.com