target/riscv: Add Zvkg ISA extension support

target/riscv: Add Zvkg ISA extension support

This commit adds support for the Zvkg vector-crypto extension, which
consists of the following instructions:

* vgmul.vv
* vghsh.vv

Translation functions are defined in
`target/riscv/insn_trans/trans_rvvk.c.inc` and helpers are defined in
`target/riscv/vcrypto_helper.c`.

Co-authored-by: Lawrence Hunter <lawrence.hunter@codethink.co.uk>
[max.chou@sifive.com: Replaced vstart checking by TCG op]
Signed-off-by: Lawrence Hunter <lawrence.hunter@codethink.co.uk>
Signed-off-by: Nazar Kazakov <nazar.kazakov@codethink.co.uk>
Signed-off-by: Max Chou <max.chou@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
[max.chou@sifive.com: Exposed x-zvkg property]
[max.chou@sifive.com: Replaced uint by int for cross win32 build]
Message-ID: <20230711165917.2629866-13-max.chou@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>