doc: Updated project doc

	- Updated WR-NIC architecture diagram (dia file uploaded too)
	- Changes in doc/wr-nic.md to update information
		- Channel 0 output is dedicated for 1-PPS signal
		- P mode removed from DIO configuration registers
		- Added new section about remote configuration with Etherbone
		- Initial channel configuration is changed
		- Updated LM32 firmware generation
dio: correct doc and comments for first channel (ch0) mode

The first channel is set with 0 so that we force it to be output mode
p/P & i/I mode will be only available for ch0, and D,d,1,0 will not be
working (they will be seen as p/P).