board/lego/ev3: fix max U-Boot flash size
The first stage bootloader on LEGO MINDSTORMS EV3 only loads the first
256K of the flash memory (this is hard-coded in an EEPROM). So, the
second stage bootloader (U-Boot) cannot exceed this size.
Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit b2e5014af5a4fe773b8bf1dd1a3fef31214eb4a7)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>