f2fs: add sbi and page pointer in f2fs_io_info

This patch adds f2fs_sb_info and page pointers in f2fs_io_info structure.
With this change, we can reduce a lot of parameters for IO functions.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 8584168..138fa93 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -520,7 +520,7 @@
 	} else {
 		f2fs_balance_fs(sbi);
 	}
-	f2fs_trace_ios(NULL, NULL, 1);
+	f2fs_trace_ios(NULL, 1);
 
 	return 0;
 }