spi: spi-geni-qcom: Remove confusing comment about setting the watermark

The comment in setup_fifo_xfer() about setting the watermark wasn't
quite proper grammar and also stopped making sense around commit
6d66507d ("spi: spi-geni-qcom: Don't wait to start 1st transfer if
transmitting"). After that commit we actually start the transfer
_before_ the watermark interrupt comes.

I don't think the comment really has any value anymore. We've already
got a comment when we grab the spinlock saying that our interrupt can
come any time as a result of the things in the locked section. Let's
just remove it.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210712085010.1.Ie3bb9f9d30d6475bb75251d32635194c1c72b9ee@changeid


Signed-off-by: Mark Brown <broonie@kernel.org>