Add 2 wishbone slave on CSR bus;
Dummy_stat_regs with fixed values and the DEBUG switch state.
Dummy_ctrl_regs with r/w regs and LEDs control.

Make packet payload size selectable and set it to 32 (x 32-bit words).
Change c_L2P_MAX_PAYLOAD to c_MAX_READ_REQ_SIZE in p2l_dma_master.

Fix bugs in DMA wishbone masters.

Modify CSR wishbone address map, BAR0 + BAR2.
Fix bug with LED.
Fix bug wb slave clk is wb clk not core clk.

Add clock input on wb bus of the core's top entity.

Lots of clean up in comments and layout.

Check L2P channel status when sending data to GN4124.