cpu: Add test to validate die_id and die_cpumask support

[sacsant]

Add comprehensive Avocado test to validate kernel commit
fb2ff9fa72e2 which added die_id and die_cpumask support for
PowerPC systems.

The test validates:

• die_id sysfs interface presence and validity
• die_cpus and die_cpus_list sysfs interfaces
• die_cpumask consistency across CPUs in same die
• die-package relationship (CPUs in same die are in same package)
• cpu_die_mask() kernel function behavior

The test handles both systems with coregroup support (die_id >= 0) and
systems without coregroup support (die_id = -1).
Code assisted by AI

Signed-off-by: Sachin Sant sachinp@linux.ibm.com

[sacsant]

Test results:

(1/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_id_presence: STARTED
(1/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_id_presence: PASS (0.02 s)
(2/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_cpumask_presence: STARTED
(2/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_cpumask_presence: PASS (0.01 s)
(3/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_id_validity: STARTED
(3/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_id_validity: PASS (0.01 s)
(4/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_cpumask_consistency: STARTED
(4/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_cpumask_consistency: PASS (0.01 s)
(5/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_package_relationship: STARTED
(5/7) cpu/cpu_die_topology.py:CPUDieTopology.test_die_package_relationship: PASS (0.01 s)
(6/7) cpu/cpu_die_topology.py:CPUDieTopology.test_cpu_die_mask_function: STARTED
(6/7) cpu/cpu_die_topology.py:CPUDieTopology.test_cpu_die_mask_function: PASS (0.01 s)
(7/7) cpu/cpu_die_topology.py:CPUDieTopology.test: STARTED
(7/7) cpu/cpu_die_topology.py:CPUDieTopology.test: PASS (0.02 s)
RESULTS : PASS 7 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | CANCEL 0
JOB TIME : 5.57 s