firmware: ti_sci: Support transfers without response

firmware: ti_sci: Support transfers without response

Check the header flags if an response is expected or not. If it is not
expected skip the receive part of ti_sci_do_xfer(). This prepares the
driver for one-way messages as prepare_sleep for Partial-IO.

Reviewed-by: Kendall Willis <k-willis@ti.com>
Signed-off-by: Markus Schneider-Pargmann (TI.com) <msp@baylibre.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Sebin Francis <sebin.francis@ti.com>
Link: https://patch.msgid.link/20251103-topic-am62-partialio-v6-12-b4-v10-1-0557e858d747@baylibre.com
Signed-off-by: Nishanth Menon <nm@ti.com>