Update of the state machine for the scalp_tx_side component.

...s/vivado/scalp_firmware/2020.2/src/hdl/scalp_firmware.vhd

ips/hw/scalp_router/src/hdl/scalp_fifo_double_register.vhd

ips/hw/scalp_router/src/hdl/scalp_misc.vhd

ips/hw/scalp_router/src/hdl/scalp_router_interface.vhd

ips/hw/scalp_router/src/hdl/scalp_tx_side.vhd

packages/hw/axi4_pkg/src/hdl/axi4_pkg.vhd