spi: rspi: Replaces "n" by "len" in qspi_transfer_*()

This patch replaced "n" by "len" bytes of data in qspi_transfer_in() and
qspi_transfer_out() function. This will make improving readability.

Signed-off-by: DongCV <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-rspi.c

···
 			for (i = 0; i < len; i++)
 				rspi_write_data(rspi, *tx++);
 		} else {
-			ret = rspi_pio_transfer(rspi, tx, NULL, n);
+			ret = rspi_pio_transfer(rspi, tx, NULL, len);
 			if (ret < 0)
 				return ret;
 		}
···
 			for (i = 0; i < len; i++)
 				*rx++ = rspi_read_data(rspi);
 		} else {
-			ret = rspi_pio_transfer(rspi, NULL, rx, n);
+			ret = rspi_pio_transfer(rspi, NULL, rx, len);
 			if (ret < 0)
 				return ret;
 		}