As this controller has a separate set and clear register, we
can't write directly to PIO_ODSR as this would required a cached
variable and would race with at91_gpio_set.
So build masks for the PIO_SODR and PIO_CODR registers and
write them together.
Signed-off-by: Alexander Stein <alexanders83@web.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>