When no MMU is used and the guest code attempts to fetch an instruction
from an invalid memory location, the exception index defaults to a data
load access fault, rather an instruction access fault.

Signed-off-by: Emmanuel Blot <emmanuel.blot@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: FB9EA197-B018-4879-AB0F-922C2047A08B@sifive.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>