stdlib: Add CustomDiskImageResource

This CustomResource can be used to specify a custom, local disk image.
It allows the user to specify the disk root partition parameter
considerably easier than when setting a disk image through a
CustomResource.

Change-Id: I8189ad065124d028aea9fab1c7f07108aa4ce6d5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53844
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
3 files changed