Fixes various bugs in lwIP and Xilinx driver and adds missing patches for hardware timestamping

Fixes at least 5 major bugs in the Xilinx driver code leading to sudden transport drops, deadlocks, interrupt blocking, memory corruption,...

lwIP core should not and as of this MR is no longer accessed from within interrupt handlers. Instead we now use deferred interrupt handling, meaning an interrupt unlocks a high priority task actually handling the event.

Introduces missing patches for hardware timestamping, including retrieval of timestamps, adjusting the hardware clock, enabling of the hardware clock, fixes for error queue handling, DOS vulnerability, select and poll handling