avr32: Allow selecting multiple pins at once

at32_select_periph() now takes an u32 bitmask rather than a single pin.
This allows to set multiple pins at once.

Signed-off-by: Alex Raimondi <mailinglist@miromico.ch>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/arch/avr32/boards/atngw100/setup.c b/arch/avr32/boards/atngw100/setup.c
index 65db3d2..6c54580 100644
--- a/arch/avr32/boards/atngw100/setup.c
+++ b/arch/avr32/boards/atngw100/setup.c
@@ -194,7 +194,7 @@
 	 * PB28/EXTINT3 doesn't; it should be SMBALERT# (for PMBus),
 	 * but it's not available off-board.
 	 */
-	at32_select_periph(GPIO_PIN_PB(28), 0, AT32_GPIOF_PULLUP);
+	at32_select_periph(GPIO_PIOB_BASE, 1 << 28, 0, AT32_GPIOF_PULLUP);
 	at32_select_gpio(i2c_gpio_data.sda_pin,
 		AT32_GPIOF_MULTIDRV | AT32_GPIOF_OUTPUT | AT32_GPIOF_HIGH);
 	at32_select_gpio(i2c_gpio_data.scl_pin,