perf arm-spe: Introduce arm_spe__is_homogeneous()

Introduce the arm_spe__is_homogeneous() function, it uses to check if
Arm SPE is homogeneous cross all CPUs.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20241003185322.192357-4-leo.yan@arm.com


Signed-off-by: Namhyung Kim <namhyung@kernel.org>