watchdog: ks8695: sink registers into driver

Commit 70adc3f32adc2fb90b0107c020678588e4cf9f51
"ARM: ks8695: merge the timer header into the timer driver"
accidentally broke the ks8695 watchdog since it was using
the timer registers in watchdog mode.

Perform the same operation here: push the registers down
into the driver, so it is self-contained, and we can keep
depopulating the <mach/*> namespace.

Reported-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Olof Johansson <olof@lixom.net>