ARM: Orion: Fix WDT compile for Dove and MV78xx0

commit 1e0c1ce00d83834d03f4d8d039734ca4703298df upstream.

Commit 0fa1f0609a0c1fe8b2be3c0089a2cb48f7fda521 (ARM: Orion: Fix
Virtual/Physical mixup with watchdog) broke the Dove & MV78xx0
build. Although these two SoC don't use the watchdog, the shared
platform code still needs to build. Add the necessary defines.

Reported-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>