fs_config Add first_stage_ramdisk/system/bin/linker[64]

Now that tune2fs and resize2fs may be dynamic, add linker[64] to
first_stage_ramdisk/system/bin.

Test: boot and examine serial output, ensure tune2fs and resize2fs
      can be executed.
Bug: 173425293

Change-Id: I35699b38ddf5004c04ec0adc1b0c54d5d9c92ae6