imx: kontron-sl-mx8mm: Remove custom board_boot_order() workaround

Nowadays detecting the SPI NOR as boot device from the ROMAPI is
fixed and works even if the SPI NOR is used as fallback boot device.

Therefore we don't need this workaround anymore.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
1 file changed