target/riscv: use RISCVException enum in exception helpers

target/riscv: use RISCVException enum in exception helpers

Do a cosmetic change in riscv_raise_exception() to change 'exception'
type from uint32_t to RISCVException, making it a bit clear that the
arg is directly correlated to the RISCVException enum.

As a side effect, change 'excp' type from int to RISCVException in
generate_exception() to guarantee that all callers of
riscv_raise_exception() will use the enum.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250106173734.412353-2-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>