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>

target/riscv/cpu_helper.c

@@ -1282,7 +1282,6 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
         if (ret == TRANSLATE_G_STAGE_FAIL) {
             first_stage_error = false;
             two_stage_indirect_error = true;
-            access_type = MMU_DATA_LOAD;
         }
 
         qemu_log_mask(CPU_LOG_MMU,