arch/riscv: Don't set up virtual memory
Due to changes in the RISC-V Privileged Architecture specification,
Linux can now be started in physical memory and it will setup its own
page tables.
Thus we can delete most of virtual_memory.c.
Change-Id: I4e69d15f8ee540d2f98c342bc4ec0c00fb48def0
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-on: https://review.coreboot.org/23772
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>