perf/x86: Make merge_attr() global to use from perf_event_intel

merge_attr() allows to merge two sysfs attribute tables.
Export it to be usable by other files too.

Next patch is going to use that to extend the sysfs format
attributes for a CPU.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1435612935-24425-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/perf_event.c

@@ -1551,7 +1551,7 @@ static void __init filter_events(struct attribute **attrs)
 }
 
 /* Merge two pointer arrays */
-static __init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
+__init struct attribute **merge_attr(struct attribute **a, struct attribute **b)
 {
 	struct attribute **new;
 	int j, i;

arch/x86/kernel/cpu/perf_event.h

@@ -795,6 +795,8 @@ static inline void set_linear_ip(struct pt_regs *regs, unsigned long ip)
 ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event);
 ssize_t intel_event_sysfs_show(char *page, u64 config);
 
+struct attribute **merge_attr(struct attribute **a, struct attribute **b);
+
 #ifdef CONFIG_CPU_SUP_AMD
 
 int amd_pmu_init(void);
@@ -926,6 +928,7 @@ static inline int is_ht_workaround_enabled(void)
 {
 	return !!(x86_pmu.flags & PMU_FL_EXCL_ENABLED);
 }
+
 #else /* CONFIG_CPU_SUP_INTEL */
 
 static inline void reserve_ds_buffers(void)