pinctrl: mvebu: dove: use global register regmap

Now that we have a regmap for global registers, get rid of the last
remaining hardcoded physical addresses. While at it, also remove
DOVE_ prefix from those macros.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>