f2fs: do not skip writing data pages

For data pages, let's try to flush as much as possible in background.

On /dev/pmem0,

1. dd if=/dev/zero of=/mnt/test/testfile bs=1M count=2048 conv=fsync
 Before : 800 MB/s
 After  : 1.1 GB/s

2. dd if=/dev/zero of=/mnt/test/testfile bs=1M count=2048
 Before : 1.3 GB/s
 After  : 2.2 GB/s

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 5d016a1..890bb28d 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -728,9 +728,7 @@
 
 	nr_to_write = wbc->nr_to_write;
 
-	if (type == DATA)
-		desired = 4096;
-	else if (type == NODE)
+	if (type == NODE)
 		desired = 3 * max_hw_blocks(sbi);
 	else
 		desired = MAX_BIO_BLOCKS(sbi);