ARM: 8832/1: NOMMU: Limit visibility for CONFIG_FLASH_{MEM_BASE,SIZE}

It looks like usage of CONFIG_FLASH_{MEM_BASE,SIZE} is limited with:

arch/arm/mm/proc-arm740.S
arch/arm/mm/proc-arm940.S
arch/arm/mm/proc-arm946.S

So it might look confusing to see the option for anything except these.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>