Revert "[usb_rs]: enumerate_devices uses a cached sysfs map"

This reverts commit 9023b052feebf6eaa16fb98898f70d9ecb01ec9d.

Reason for revert: b/441715181

Original change's description:
> [usb_rs]: enumerate_devices uses a cached sysfs map
>
> Cuts down time to enumerate the devices by calculating a map of device id to
> sysfs path and then passing that to the
> DeviceHandleInner::new_with_sysfs() function so it can pull the serial
> number faster.
>
> Also now cache the sysfs path in the DeviceHandleInner as an
> Option<PathBuf>
>
> Test: build the binary and execute `ffx target list` to see the fastboot
> devices enumerated
> Change-Id: Idfa68cd14f61b722ad28ed84e45693676a6a636c
> Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1351296
> Fuchsia-Auto-Submit: Colin Nelson <colnnelson@google.com>
> Reviewed-by: Casey Dahlin <sadmac@google.com>
> Commit-Queue: Colin Nelson <colnnelson@google.com>

Change-Id: Ic1a392a9f19947263b1cc78892cbedbc7fffda4c
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1357170
Reviewed-by: RubberStamper 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Commit-Queue: Brian Bosak <bbosak@google.com>