pinctrl: abx500: remove strict mode

Commit a21763a0
"pinctrl: nomadik: activate strict mux mode"
put all Nomadik pin controllers to strict mode. This was
not good on the Snowball platform: the muxing of GPIOs to
different pins is done with hogs in the DTS file, and then
these GPIOs are used by offset, relying on hogs to mux the
pins. Since that means the pin controller "owns" the pins
and at the same time we have a GPIO user, this pin controller
is by definition not strict.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>