target/riscv: Simplify counter predicate function

target/riscv: Simplify counter predicate function

All the hpmcounters and the fixed counters (CY, IR, TM) can be represented
as a unified counter. Thus, the predicate function doesn't need handle each
case separately.

Simplify the predicate function so that we just handle things differently
between RV32/RV64 and S/HS mode.

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221701.41932-3-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>