We are not doing any dma here, it's just an SPI transaction. Name them
only rx/tx (although io_packet_tx/io_packet_rx could be another option).
This also zero-initialize the struct to keep valgrind happy about not
calling ioctl() with uninitialized variables.
The PSTR is already define as a NOP for all supported platforms. It's
only needed for AVR so here we remove all the uses throughout the
codebase.
This was automated with a simple python script so it also converts
places which spans to multiple lines, removing the matching parentheses.
AVR-specific places were not changed.
Lucas De Marchi
Pritam Ghanghas
Caio Marcelo de Oliveira Filho
Andrew Tridgell
raspilot