Fixes e.g. SPI flash access on BCM6358/BCM6368. Transfers < 256 bytes are not affected. Signed-off-by: Jonas Gorski <jogo@openwrt.org> git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39265 3c298f89-4303-0410-b956-a3cf2f4a3e73