ext4: revert buggy trim overflow patch

This reverts commit 4f531501: ext4: fix possible overflow in
ext4_trim_fs()
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/mballoc.c

@@ -4804,7 +4804,6 @@ ext4_grpblk_t ext4_trim_all_free(struct super_block *sb, struct ext4_buddy *e4b,
 int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 {
 	struct ext4_buddy e4b;
-	ext4_fsblk_t blocks_count = ext4_blocks_count(EXT4_SB(sb)->s_es);
 	ext4_group_t first_group, last_group;
 	ext4_group_t group, ngroups = ext4_get_groups_count(sb);
 	ext4_grpblk_t cnt = 0, first_block, last_block;
@@ -4816,11 +4815,6 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	minlen = range->minlen >> sb->s_blocksize_bits;
 	trimmed = 0;
 
-	if (start >= blocks_count)
-		return -EINVAL;
-	if (start + len > blocks_count)
-		len = blocks_count - start;
-
 	if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb)))
 		return -EINVAL;