target/riscv: Set the correct exception for implict G-stage translation fail

target/riscv: Set the correct exception for implict G-stage translation fail

The privileged spec states:
For a memory access made to support VS-stage address translation (such as
to read/write a VS-level page table), permissions are checked as though
for a load or store, not for the original access type. However, any
exception is always reported for the original access type (instruction,
load, or store/AMO).

The current implementation converts the access type to LOAD if implicit
G-stage translation fails which results in only reporting "Load guest-page
fault". This commit removes the convertion of access type, so the reported
exception conforms to the spec.

Signed-off-by: Jason Chien <jason.chien@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230627074915.7686-1-jason.chien@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>