NET: pass source IP address to packet handlers

This is needed for the upcoming TFTP server implementation.

This also simplifies PingHandler() and fixes rxhand_f documentation.

Signed-off-by: Luca Ceresoli <luca.ceresoli@comelit.it>
Cc: Wolfgang Denk <wd@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
9 files changed