The watchdog infrastructure in Dove is no different from that in
Orion5x or Kirkwood, so let's enable it for Dove.  The only things
missing are a few register settings in Dove's bridge-regs.h.

Rather than duplicating the same register bit masks for the RSTOUTn_MASK
and BRIDGE_CAUSE registers, move the definitions into the watchdog
driver itself.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>