input/protocoldata: improve use of feed queue API

input/protocoldata: improve use of feed queue API

Improve feed queue related calls in the submission of capture start/end
idle phases, inter-frame idle phases, and bit time quanta of generated
protocol traffic. The submit-one API call accepts a repeat count which
eliminates caller's loops.

This also happens to eliminate a misguided yet harmless wrong use of the
feed queue API. An earlier implementation assumed "data pointer, and
data size" as arguments, and looped around that at the caller's. While
it's "data pointer, and repeat count". Used to work because sizeof(u8)
"was mistaken" as repeat count 1, so this flaw went unnoticed.

Propagate errors as they are seen, an earlier implementation silently
ignored them for frame payloads.