Revert "loop: take the file system minimum dio alignment into account"

This reverts commit f4774e92.

It breaks LTP's ioctl_loop05 test for LOOP_SET_DIRECT_IO and can be
brought back after this problem is resolved.

  ioctl_loop05.c:84: TFAIL: LOOP_SET_DIRECT_IO failed: EINVAL (22)

Bug: 411076727
Change-Id: Id57935fb51ca2691e218fec7e867235687da1173
Signed-off-by: Carlos Llamas <cmllamas@google.com>