bcm63xx: ad1018: remove cfe.bin image support
Apparently, Sercomm allows loading a BCM WFI image via CFE, but this image
destroys "serial" and "protect" nand partitions, which is wrong.
It will also set both bootflags to the same value, which causes booting
issues with cferam (cferom will alternatively boot from cferam1 or cferam2
each time the device is rebooted).
Now that OEM Sercomm images are supported it's time to remove this hacky
cfe.bin image support.
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>