powerpc/sparse: Make a bunch of things static

Squash a bunch of sparse warnings by making things static.

Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/perf/power9-pmu.c

@@ -119,7 +119,7 @@ static struct attribute *power9_pmu_format_attr[] = {
 	NULL,
 };
 
-struct attribute_group power9_pmu_format_group = {
+static struct attribute_group power9_pmu_format_group = {
 	.name = "format",
 	.attrs = power9_pmu_format_attr,
 };