ar71xx: only use SPI NOR 4K sectors on smaller flash chips for mikrotik devices
On NOR based Mikrotik devices, 4K sectors significantly slow down
firmware flashing and jffs2 usage. On NAND based devices they may be
necessary to run rbcfg (the boot loader config is often on SPI NOR).
Signed-off-by: Felix Fietkau <[email protected]>
Felix Fietkau