perf: Fix __percpu annotation

With bcecd5a ("percpu: repurpose __percpu tag as a named address
space qualifier") the normal compilers start caring about the __percpu
annotation, as such f67d1ff ("perf/core: Detach 'struct
perf_cpu_pmu_context' and 'struct pmu' lifetimes") needs a fixup.

Fixes: f67d1ff ("perf/core: Detach 'struct perf_cpu_pmu_context' and 'struct pmu' lifetimes")
Fixes: bcecd5a ("percpu: repurpose __percpu tag as a named address space qualifier")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: jirislaby@kernel.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Author: Peter Zijlstra

include/linux/perf_event.h

@@ -343,7 +343,7 @@ struct pmu {
 	 */
 	unsigned int			scope;
 
-	struct perf_cpu_pmu_context __percpu **cpu_pmu_context;
+	struct perf_cpu_pmu_context * __percpu *cpu_pmu_context;
 	atomic_t			exclusive_cnt; /* < 0: cpu; > 0: tsk */
 	int				task_ctx_nr;
 	int				hrtimer_interval_ms;