ARM: footbridge: mark cats board for removal

There are three remaining footbridge boards, as the CO285 and the HP
personal server got removed already over the years.

Russell still uses his ebsa285, while both Linus and Marc have a NetWinder
that they use for testing. Nobody so far replied that they are using cats,
so it goes on the long list of machines to be removed in early 2023 if
it stays like this.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Linus Walleij <linusw@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/configs/footbridge_defconfig

@@ -5,7 +5,6 @@ CONFIG_BLK_DEV_INITRD=y
 CONFIG_EXPERT=y
 # CONFIG_HOTPLUG is not set
 CONFIG_ARCH_FOOTBRIDGE=y
-CONFIG_ARCH_CATS=y
 CONFIG_ARCH_EBSA285_HOST=y
 CONFIG_ARCH_NETWINDER=y
 CONFIG_FPE_NWFPE=y

arch/arm/mach-footbridge/Kconfig

@@ -5,6 +5,7 @@ menu "Footbridge Implementations"
 
 config ARCH_CATS
 	bool "CATS"
+	depends on UNUSED_BOARD_FILES
 	select CLKEVT_I8253
 	select CLKSRC_I8253
 	select FOOTBRIDGE_HOST