It was assumed that we should send all the data following a "program"
request to the device, before sending a ZLP. But on SDM845 it's seen
that not sending a ZLP after each chunk sometimes causes the
communication to stall.

Given that the "program" request already carries the information about
how much data will be transferred there should be no issues with sending
additional ZLPs, so do this.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>