wr_si57x_interface: latch the current RFREQ value before writing it to the device (prevents changes of the RFREQ while I2C is still busy)

wr_board_pkg: declare eb_ethernet_slave as a component so that compiler doesn't complain when EB repo is not included

New statistics data was added to diag/snmp array. To ensure
backward-comapatibity between MIB versions, this new data needs
to be added at the end. Thus, now we need to inject dbg_word and
magic number in the middle.

The diag_ver is not bumped because the change is backward-compatible.

This was previously implemented but got lost when the fixed latency
instreamers was re-done. The idea is to compensate for internal
delays, so that the tx/rx_valid signals are as close to the
configured latency as possible.

Corrected simulation accordingly: the simulation also corrected for
delays.