Revert^2 "Add the 'bdev_type' attribute to all block devices" am: c4af45caa3 am: fe29feffc6 am: 054cbc981b

Original change: https://android-review.googlesource.com/c/device/linaro/poplar/+/1862221

Change-Id: Ib11e82e9128f82c174724f95e56395dbac157dfe