To support DM QSPI driver
- Add spi0 and spi1 alias for qspi1 and qspi2.
- Add -u-boot.dtsi to modify n25q256a@0 and n25q256a@1 compatible string
to "spi-flash" and add "num-cs" property.
- Enable DM SPI/QSPI relavent configurations
- Remove iomux settings of qspi2 in board codes which is not needed
for DM driver.
- Add sf default settings. So running "sf probe" can detect the flash
Signed-off-by: Ye Li <ye.li@nxp.com>
