To support QSPI DM driver
- Add spi0 alias for qspi node. Which is used for bus number 0.
- Modify the n25q256a@0 compatible property to "spi-flash".
- Modify spi4 (gpio_spi) node to spi5
- Define DM SPI/QSPI related config to enable QSPI
Signed-off-by: Peng Fan <peng.fan@nxp.com>