target/riscv/cpu.c: split CPU options from riscv_cpu_extensions[]

target/riscv/cpu.c: split CPU options from riscv_cpu_extensions[]

We'll add a new CPU type that will enable a considerable amount of
extensions. To make it easier for us we'll do a few cleanups in our
existing riscv_cpu_extensions[] array.

Start by splitting all CPU non-boolean options from it. Create a new
riscv_cpu_options[] array for them. Add all these properties in
riscv_cpu_add_user_properties() as it is already being done today.

'mmu' and 'pmp' aren't really extensions in the usual way we think about
RISC-V extensions. These are closer to CPU features/options, so move
both to riscv_cpu_options[] too. In the near future we'll need to match
all extensions with all entries in isa_edata_arr[], and so it happens
that both 'mmu' and 'pmp' do not have a riscv,isa string (thus, no priv
spec version restriction). This further emphasizes the point that these
are more a CPU option than an extension.

No functional changes made.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-ID: <20230912132423.268494-2-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>