powerpc/secvar: Use sysfs_emit() instead of sprintf()

The secvar format string and object size sysfs files are both ASCII
text, and should use sysfs_emit().  No functional change.
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230210080401.345462-7-ajd@linux.ibm.com

arch/powerpc/kernel/secvar-sysfs.c

@@ -35,7 +35,7 @@ static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr,
 	if (rc)
 		goto out;
 
-	rc = sprintf(buf, "%s\n", format);
+	rc = sysfs_emit(buf, "%s\n", format);
 
 out:
 	of_node_put(node);
@@ -57,7 +57,7 @@ static ssize_t size_show(struct kobject *kobj, struct kobj_attribute *attr,
 		return rc;
 	}
 
-	return sprintf(buf, "%llu\n", dsize);
+	return sysfs_emit(buf, "%llu\n", dsize);
 }
 
 static ssize_t data_read(struct file *filep, struct kobject *kobj,