ARM: dts: at91: sama5d27_som1_ek: update pinmux/pinconf for LEDs and USB

There are some changes from the prototype board concerning LEDs and USB
pins:
- USBB power enable and red LED pins are inverted.
- The polarity of LEDs is inverted too.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>