Use common macro PMU_EVENT_ATTR_ID to simplify ARMV8_EVENT_ATTR

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Qi Liu <liuqi115@huawei.com>
Link: https://lore.kernel.org/r/1623220863-58233-8-git-send-email-liuqi115@huawei.comSigned-off-by: Will Deacon <will@kernel.org>