powerpc/perf/hv-24x7: Make some symbols static

The sparse tool complains as follows:

arch/powerpc/perf/hv-24x7.c:229:1: warning:
 symbol '__pcpu_scope_hv_24x7_txn_flags' was not declared. Should it be static?
arch/powerpc/perf/hv-24x7.c:230:1: warning:
 symbol '__pcpu_scope_hv_24x7_txn_err' was not declared. Should it be static?
arch/powerpc/perf/hv-24x7.c:236:1: warning:
 symbol '__pcpu_scope_hv_24x7_hw' was not declared. Should it be static?
arch/powerpc/perf/hv-24x7.c:244:1: warning:
 symbol '__pcpu_scope_hv_24x7_reqb' was not declared. Should it be static?
arch/powerpc/perf/hv-24x7.c:245:1: warning:
 symbol '__pcpu_scope_hv_24x7_resb' was not declared. Should it be static?

This symbol is not used outside of hv-24x7.c, so this
commit marks it static.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210409090124.59492-1-cuibixuan@huawei.com

arch/powerpc/perf/hv-24x7.c

@@ -226,14 +226,14 @@ static struct attribute_group event_long_desc_group = {
 
 static struct kmem_cache *hv_page_cache;
 
-DEFINE_PER_CPU(int, hv_24x7_txn_flags);
-DEFINE_PER_CPU(int, hv_24x7_txn_err);
+static DEFINE_PER_CPU(int, hv_24x7_txn_flags);
+static DEFINE_PER_CPU(int, hv_24x7_txn_err);
 
 struct hv_24x7_hw {
 	struct perf_event *events[255];
 };
 
-DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw);
+static DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw);
 
 /*
  * request_buffer and result_buffer are not required to be 4k aligned,
@@ -241,8 +241,8 @@ DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw);
  * the simplest way to ensure that.
  */
 #define H24x7_DATA_BUFFER_SIZE	4096
-DEFINE_PER_CPU(char, hv_24x7_reqb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
-DEFINE_PER_CPU(char, hv_24x7_resb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
+static DEFINE_PER_CPU(char, hv_24x7_reqb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
+static DEFINE_PER_CPU(char, hv_24x7_resb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
 
 static unsigned int max_num_requests(int interface_version)
 {