powerpc/powernv: Make some symbols static

Fix sparse warnings:

  arch/powerpc/platforms/powernv/opal-psr.c:20:1:
   warning: symbol 'psr_mutex' was not declared. Should it be static?
  arch/powerpc/platforms/powernv/opal-psr.c:27:3:
   warning: symbol 'psr_attrs' was not declared. Should it be static?
  arch/powerpc/platforms/powernv/opal-powercap.c:20:1:
   warning: symbol 'powercap_mutex' was not declared. Should it be static?
  arch/powerpc/platforms/powernv/opal-sensor-groups.c:20:1:
   warning: symbol 'sg_mutex' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190702131733.44100-1-yuehaibing@huawei.com

arch/powerpc/platforms/powernv/opal-powercap.c

@@ -13,7 +13,7 @@
 
 #include <asm/opal.h>
 
-DEFINE_MUTEX(powercap_mutex);
+static DEFINE_MUTEX(powercap_mutex);
 
 static struct kobject *powercap_kobj;
 

arch/powerpc/platforms/powernv/opal-psr.c

@@ -13,11 +13,11 @@
 
 #include <asm/opal.h>
 
-DEFINE_MUTEX(psr_mutex);
+static DEFINE_MUTEX(psr_mutex);
 
 static struct kobject *psr_kobj;
 
-struct psr_attr {
+static struct psr_attr {
 	u32 handle;
 	struct kobj_attribute attr;
 } *psr_attrs;

arch/powerpc/platforms/powernv/opal-sensor-groups.c

@@ -13,7 +13,7 @@
 
 #include <asm/opal.h>
 
-DEFINE_MUTEX(sg_mutex);
+static DEFINE_MUTEX(sg_mutex);
 
 static struct kobject *sg_kobj;