mtd: rawnand: fsl_ifc: fixup SRAM init for newer ctrl versions

Newer versions of the IFC controller use a different method of initializing the
internal SRAM: Instead of reading from flash, a bit in the NAND configuration
register has to be set in order to trigger the self-initializing process.

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>