common: unify _require_batched_discard

To check for FITRIM tests used  _require_fstrim() and
_test_batched_discard() but as _test_batched_discard() already
includes _test_fstrim() unify FSTRIM check throughout xfstests with
_require_batched_discard().

Signed-off-by: Dushan Tcholich <dusanc@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/generic/038

@@ -69,7 +69,6 @@ _need_to_be_root
 _supported_fs generic
 _supported_os Linux
 _require_scratch
-_require_fstrim
 
 rm -f $seqres.full
 
@@ -123,6 +122,7 @@ create_files()
 _scratch_mkfs >>$seqres.full 2>&1
 _require_fs_space $SCRATCH_MNT $((10 * 1024 * 1024))
 _scratch_mount
+_require_batched_discard $SCRATCH_MNT
 
 for ((i = 0; i < $((4 * $LOAD_FACTOR)); i++)); do
 	trim_loop &