blackfin: Fit u-boot image size into limited nor flash on blackfin.

- Disable NAND driver on bf537-stamp.
- Make MMC_SPI optional.
- Disable LCD driver on bf527-ezkit.
- Enlarge BF609 nor flash reserved size from 256k to 512k bytes.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Sonic Zhang <sonic.adi@gmail.com>
3 files changed