spi: spi-qpic-snand: use NANDC_STEP_SIZE consistently

Change the qcom_spi_read_page_ecc() function to use NANDC_STEP_SIZE
instead of a magic number while calculating the data size to keep it
consistent with other functions like qcom_spi_program_{raw,ecc,oob}
and qcom_spi_read_cw_{raw,page_oob}.

No functional changes.

Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Reviewed-by: Md Sadre Alam <quic_mdalam@quicinc.com>
Link: https://patch.msgid.link/20250525-qpic-snand-nandc_step_size-v1-1-6039e9bfe1c6@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: juhosg

drivers/spi/spi-qpic-snand.c

@@ -835,7 +835,7 @@ static int qcom_spi_read_page_ecc(struct qcom_nand_controller *snandc,
 		int data_size, oob_size;
 
 		if (i == (num_cw - 1)) {
-			data_size = 512 - ((num_cw - 1) << 2);
+			data_size = NANDC_STEP_SIZE - ((num_cw - 1) << 2);
 			oob_size = (num_cw << 2) + ecc_cfg->ecc_bytes_hw +
 				    ecc_cfg->spare_bytes;
 		} else {