f2fs: enable fstrim to issue discard while using discard option

MIUI-1428085

The discard thread can only process 8 requests at a time by default.
So fstrim need to handle the remaining discard requests while using
discard option.

Change-Id: I5eac38c34182607e8dceeb13273522b10ce02af8
Signed-off-by: liuchao12 <liuchao12@xiaomi.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: onettboots <blackcocopet@gmail.com>

Author: liuchao12

fs/f2fs/segment.c

@@ -3162,15 +3162,6 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 	if (err)
 		goto out;
 
-	/*
-	 * We filed discard candidates, but actually we don't need to wait for
-	 * all of them, since they'll be issued in idle time along with runtime
-	 * discard option. User configuration looks like using runtime discard
-	 * or periodic fstrim instead of it.
-	 */
-	if (f2fs_realtime_discard_enable(sbi))
-		goto out;
-
 	start_block = START_BLOCK(sbi, start_segno);
 	end_block = START_BLOCK(sbi, end_segno + 1);