pinctrl: demote dev_info on successful probes to dev_dbg ...

The SoC's pin controller is virtually always built and probed, so
there's is little information to gain from the fact it was successfully
probed. Have the success message show up as debug message to reduce probe
clutter like this:

	NOTICE: stm32-pinctrl soc:pin-controller@50002000.of: pinctrl/gpio driver registered
	NOTICE: stm32-pinctrl soc:pin-controller-z@54004000.of: pinctrl/gpio driver registered

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

pinctrl: add gpio and pinctrl driver for sama5d2 PIO4 ...

The sama5d2 features a GPIO and pin controller different than the one
we support in barebox. The device tree bindings are different as well,
so it makes sense to have a separate driver for it.

Add the pin control and GPIO driver as well as some helpers usable
from PBL, should we want to do pinmuxing that early.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>