uboot-imx

arm: zynq: Move CONFIG_SF_DUAL_FLASH to defconfig

Move the only use of CONFIG_SF_DUAL_FLASH to defconfig. This makes the
associated topic_miamiplus.h header obsolete, so remove that as well.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>