The PCA muxes now depend on I2C_MUX. SPI si now required by SPI-NOR.

Add the eMMC driver, and remove the FSI SBEFIFO which is not used on AST2400
systems.

The remaining changes are cleanups from regenerating the defconfig.
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Joel Stanley <joel@jms.id.au>