f2fs: introduce f2fs_cp_error for readability

This patch adds f2fs_cp_error for readability.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cc89a7f..2d009ae 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1096,6 +1096,11 @@
 	return sb->s_flags & MS_RDONLY;
 }
 
+static inline bool f2fs_cp_error(struct f2fs_sb_info *sbi)
+{
+	return is_set_ckpt_flags(sbi->ckpt, CP_ERROR_FLAG);
+}
+
 static inline void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi)
 {
 	set_ckpt_flags(sbi->ckpt, CP_ERROR_FLAG);