file: ensure cleanup

file: ensure cleanup

Brown paper bag time. This is a silly oversight where I missed to drop
the error condition checking to ensure we clean up on early error
returns. I have an internal unit testset coming up for this which will
catch all such issues going forward.

Reported-by: Chris Mason <clm@fb.com>
Reported-by: Jeff Layton <jlayton@kernel.org>
Fixes: 011703a9acd7 ("file: add FD_{ADD,PREPARE}()")
Signed-off-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>