applet.program_ice40: remove manual chunked writes

[kbeckmann]

The previous code didn't build anymore. This was because we tried to
write [0] which isn't supported anymore because of the memoryview()
usage. Perhaps that should be fixed instead?

support.chunked_fifo implements the chunked writes instead now.

[whitequark]

This of course doesn't work since gateware performs dechunking in program_ice40. Have you tested it on real hardware?

[kbeckmann]

Ouch. Good point, no I just checked with a logic analyser. I'll change the commit to just remove the [0] stuff. Or what should we do about that? Fix it in the chunked_fifo?

[whitequark]

Ideally this should inherit from spi-master.

[whitequark]

But the bug you found should also be fixed; fifo.write([0]) is supposed to work. It's in DirectAccessMultiplexer.

[kbeckmann]

Alright, then I'll close this. Sorry for the noise.