flash.h: Remove CONFIG_SYS_FLASH_CFI from flash_info_t

Those embers wrapped with CONFIG_SYS_FLASH_CFI in struct flash_info_t
are unconditionally used in the cfi_flash.c driver.

Drop the #ifdefs in the definition of flash_info_t.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>