powerpc/papr_scm: Ensure rc is always initialized in papr_scm_pmu_register()

Clang warns:

arch/powerpc/platforms/pseries/papr_scm.c:492:6: warning: variable 'rc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]

          if (!p->stat_buffer_len)
              ^~~~~~~~~~~~~~~~~~~
  arch/powerpc/platforms/pseries/papr_scm.c:523:64: note: uninitialized use occurs here
          dev_info(&p->pdev->dev, "nvdimm pmu didn't register rc=%d\n", rc);
                                                                        ^~
  include/linux/dev_printk.h:150:67: note: expanded from macro 'dev_info'
          dev_printk_index_wrap(_dev_info, KERN_INFO, dev, dev_fmt(fmt), ##__VA_ARGS__)
                                                                          ^~~~~~~~~~~
  include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
                  _p_func(dev, fmt, ##__VA_ARGS__);                       \
                                      ^~~~~~~~~~~
  arch/powerpc/platforms/pseries/papr_scm.c:492:2: note: remove the 'if' if its condition is always false
          if (!p->stat_buffer_len)
          ^~~~~~~~~~~~~~~~~~~~~~~~
  arch/powerpc/platforms/pseries/papr_scm.c:484:8: note: initialize the variable 'rc' to silence this warning
          int rc, nodeid;
                ^
                = 0

1 warning generated.

The call to papr_scm_pmu_check_events() was eliminated but a return code was not added to the if statement. Add the same return code from papr_scm_pmu_check_events() for this condition so there is no more warning.

---
 arch/powerpc/platforms/pseries/papr_scm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index 54740af21557..2f8385523a13 100644
@@ -489,8 +489,10 @@ static void papr_scm_pmu_register(struct papr_scm_priv *p)
 		goto pmu_err_print;
 	}
 
-	if (!p->stat_buffer_len)
+	if (!p->stat_buffer_len) {
+		rc = -ENOENT;
 		goto pmu_check_events_err;
+	}
 
 	nd_pmu->pmu.task_ctx_nr = perf_invalid_context;
 	nd_pmu->pmu.name = nvdimm_name(p->nvdimm);

base-commit: 91926d8b7e71aaf5f84f0cf208fc5a8b7a761050

2.37.2

Applied to powerpc/fixes.

[1/1] powerpc/papr_scm: Ensure rc is always initialized in papr_scm_pmu_register()

      https://git.kernel.org/powerpc/c/6cf07810e9ef8535d60160d13bf0fd05f2af38e7

cheers