drm/panel: sitronix-st7789v: simplify st7789v_spi_write

st7789v_spi_write initializes a message with just
a single transfer, spi_sync_transfer can be used
for that.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-7-sre@kernel.org

drivers/gpu/drm/panel/panel-sitronix-st7789v.c

@@ -129,17 +129,13 @@ static int st7789v_spi_write(struct st7789v *ctx, enum st7789v_prefix prefix,
 			     u8 data)
 {
 	struct spi_transfer xfer = { };
-	struct spi_message msg;
 	u16 txbuf = ((prefix & 1) << 8) | data;
 
-	spi_message_init(&msg);
-
 	xfer.tx_buf = &txbuf;
 	xfer.bits_per_word = 9;
 	xfer.len = sizeof(txbuf);
 
-	spi_message_add_tail(&xfer, &msg);
-	return spi_sync(ctx->spi, &msg);
+	return spi_sync_transfer(ctx->spi, &xfer, 1);
 }
 
 static int st7789v_write_command(struct st7789v *ctx, u8 cmd)