spi: airoha: fix airoha_snand_{write,read}_data data_len estimation

Fix data length written and read in airoha_snand_write_data and
airoha_snand_read_data routines respectively if it is bigger than
SPI_MAX_TRANSFER_SIZE.

Fixes: a403997 ("spi: airoha: add SPI-NAND Flash controller driver")
Tested-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20240913-airoha-spi-fixes-v1-2-de2e74ed4664@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: LorenzoBianconi

drivers/spi/spi-airoha-snfi.c

@@ -405,7 +405,7 @@ static int airoha_snand_write_data(struct airoha_snand_ctrl *as_ctrl, u8 cmd,
 	for (i = 0; i < len; i += data_len) {
 		int err;
 
-		data_len = min(len, SPI_MAX_TRANSFER_SIZE);
+		data_len = min(len - i, SPI_MAX_TRANSFER_SIZE);
 		err = airoha_snand_set_fifo_op(as_ctrl, cmd, data_len);
 		if (err)
 			return err;
@@ -427,7 +427,7 @@ static int airoha_snand_read_data(struct airoha_snand_ctrl *as_ctrl, u8 *data,
 	for (i = 0; i < len; i += data_len) {
 		int err;
 
-		data_len = min(len, SPI_MAX_TRANSFER_SIZE);
+		data_len = min(len - i, SPI_MAX_TRANSFER_SIZE);
 		err = airoha_snand_set_fifo_op(as_ctrl, 0xc, data_len);
 		if (err)
 			return err;