DMAENGINE: correct PL080 register header file

This PL008 among all other variables named PL080 doesn't seem
right. Fix it. Also add some missing defined that I use in the
new PL08x driver.

Acked-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>