verilator_tb_utils: adds jtag_vpi support

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
or1200-generic: use jtag_vpi from verilator_tb_utils

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
jtag_vpi: update core file to add verilator files

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>