tst-statfs: print f_frsize if available

Follow-up of 68de9946e914d8c30dcc6667a059ea59e5b74cac

Signed-off-by: Eugene Rudoy <gene.devel@gmail.com>

test/misc/tst-statfs.c

@@ -19,6 +19,9 @@ main(int argc, char* argv[])
 		++ret;
 		printf("statfs %s:\n\tblocks=%lld\n\tblkfree=%lld\n\tbsize=%d\n",
 			argv[i], s.f_blocks, s.f_bfree, s.f_bsize);
+#ifdef _STATFS_F_FRSIZE
+		printf("\tfrsize=%lld\n", s.f_frsize);
+#endif
 	}
 	exit(ret ? EXIT_SUCCESS : EXIT_FAILURE);
 }