ext4: add FITRIM to compat_ioctl.

FITRIM isn't added in compat_ioctl. So a 32 bit program can't be executed
in a 64 bit platform. Add it in the compat_ioctl.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>