staging: erofs: add two missing erofs_workgroup_put for corrupted images

staging: erofs: add two missing erofs_workgroup_put for corrupted images

As reported by erofs-utils fuzzer, these error handling
path will be entered to handle corrupted images.

Lack of erofs_workgroup_puts will cause unmounting
unsuccessfully.

Fix these return values to EFSCORRUPTED as well.

Fixes: 1117b3581300 ("staging: erofs: introduce VLE decompression support")
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20190819103426.87579-4-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>