cfi: rename CFG_FLASH_CFI_DRIVER to CONFIG_FLASH_CFI_DRIVER

Commit	00b1883a
missed a few boards:
	include/configs/M5253DEMO.h
	include/configs/ml507.h
	include/configs/redwood.h

This patch fixes this.

Signed-off-by: Heiko Schocher <hs@denx.de>