Drop the bogus uart_write_wakeup() from when setting up a new DMA
transfer, which does not free up any more space in the ring buffer.

Any pending writers will be woken up when the transfer completes.

Cc: stable <stable@kernel.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sa8540p-ride
Link: https://lore.kernel.org/r/20230307164405.14218-5-johan+linaro@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>