MLK-15958-1 mtd: spi: Add 4bytes extend address support

MLK-15958-1 mtd: spi: Add 4bytes extend address support

Current SPI flash framework only supports to set bank register
(CONFIG_SPI_FLASH_BAR) for flash with size > 16MiB. But some new flash device
(for example, mt35xu512aba) does not support this way, it only supports
4bytes extend address.

To access the whole memory size for such flash device, we add the support
for this 4bytes extend address mode to SPI flash framework.
The configuration CONFIG_SPI_FLASH_4BYTES_ADDR is used to enable the feature.

Signed-off-by: Ye Li <ye.li@nxp.com>