powerpc/nvram: print no error when pstore backend is not nvram

Pstore only supports one backend at a time. The preferred
pstore backend is set by passing the pstore.backend=<name>
argument to the kernel at boot time. Currently, while trying
to register with pstore, nvram throws an error message even
when "pstore.backend != nvram", which is unnecessary. This
patch removes the error message in case "pstore.backend != nvram".

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/nvram_64.c

@@ -581,9 +581,10 @@ static int nvram_pstore_init(void)
 	spin_lock_init(&nvram_pstore_info.buf_lock);
 
 	rc = pstore_register(&nvram_pstore_info);
-	if (rc != 0)
-		pr_err("nvram: pstore_register() failed, defaults to "
-				"kmsg_dump; returned %d\n", rc);
+	if (rc && (rc != -EPERM))
+		/* Print error only when pstore.backend == nvram */
+		pr_err("nvram: pstore_register() failed, returned %d. "
+				"Defaults to kmsg_dump\n", rc);
 
 	return rc;
 }