drivers: perf: arm_pmuv3: Drop some unused arguments from armv8_pmu_init()

drivers: perf: arm_pmuv3: Drop some unused arguments from armv8_pmu_init()

All the PMU init functions want the default sysfs attribute groups, and so
these all call armv8_pmu_init_nogroups() helper, with none of them calling
armv8_pmu_init() directly. When we introduced armv8_pmu_init_nogroups() in
the commit e424b1798526 ("arm64: perf: Refactor PMU init callbacks")

 ... we thought that we might need custom attribute groups in future, but
as we evidently haven't, we can remove the option.

This patch folds armv8_pmu_init_nogroups() into armv8_pmu_init(), removing
the ability to use custom attribute groups and simplifying the code.

CC: James Clark <james.clark@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20231016025436.1368945-1-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>