generic/052: use _check_scratch_fs not _xfs_check

generic/052 was made generic from an xfs test, and generic functions
should be used not the xfs-specific ones.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/generic/052

@@ -72,7 +72,7 @@ _print_logstate
 
 # curious if FS consistent at start
 if false; then
-    if _xfs_check $SCRATCH_DEV; then
+    if _check_scratch_fs; then
        echo "*** checked ok ***"
     fi
 fi