spi: spi-fsl-lpspi: Parameterize reading num-cs from hardware

Add query_hw_for_num_cs in devtype to avoid directly checking compatible
string "fsl,imx93-spi".

No functionality change.

Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20250828-james-nxp-lpspi-v2-8-6262b9aa9be4@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: james-c-linaro

drivers/spi/spi-fsl-lpspi.c

@@ -87,6 +87,7 @@
 
 struct fsl_lpspi_devtype_data {
 	u8 prescale_max : 3; /* 0 == no limit */
+	bool query_hw_for_num_cs : 1;
 };
 
 struct lpspi_config {
@@ -137,6 +138,7 @@ struct fsl_lpspi_data {
  */
 static const struct fsl_lpspi_devtype_data imx93_lpspi_devtype_data = {
 	.prescale_max = 1,
+	.query_hw_for_num_cs = true,
 };
 
 static const struct fsl_lpspi_devtype_data imx7ulp_lpspi_devtype_data = {
@@ -932,7 +934,7 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
 	fsl_lpspi->rxfifosize = 1 << ((temp >> 8) & 0x0f);
 	if (of_property_read_u32((&pdev->dev)->of_node, "num-cs",
 				 &num_cs)) {
-		if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx93-spi"))
+		if (devtype_data->query_hw_for_num_cs)
 			num_cs = ((temp >> 16) & 0xf);
 		else
 			num_cs = 1;