arch-riscv: Added DTB Generation Functionality to RISC-V FS

Changes:
1. RiscvBareMetal
The RiscvBareMetal class and API are preserved for backwards
compatibility, but the base class RiscvFSWorkload is removed
as it inherits from the Workload class. However, most needed
functionalities are already implemented in the KernelWorkload
class

2. RiscvLinux
The RiscvLinux class is added. A dtb filename can be specified
to be loaded to the corresponding memory address.

3. HiFive, Clint, Plic, Uart8250, VirtIOMMIO
Devicetree node generation function is added.

4. tlb, faults
Unnecessary includes of arch/riscv/fs_workload are removed.

Change-Id: Ia239b5614bd93d8e794330ead266f6121a4d13cb
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/42053
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ayaz Akram <yazakram@ucdavis.edu>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
15 files changed