gitlab-ci.d/crossbuilds: add riscv64 KVM-only build job

Add CI coverage for a riscv64 --disable-tcg cross build. This ensures that RISC-V no-TCG/KVM-only builds keep working and prevents TCG-only code from being accidentally pulled into common RISC-V sources again. The cross_accel_build_job template enables KVM by default via --enable-${ACCEL:-kvm}, so the extra options only need to disable TCG. Signed-off-by: Zephyr Li <fritchleybohrer@gmail.com> Reviewed-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-ID: <20260703180538.3346781-25-daniel.barboza@oss.qualcomm.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>