ARM: at91/dt: introduce atmel,<chip>-dbgu

The DBGU is not a simple UART and we need to be able to distinguish it from the
other UARTs, in particular to get its address and check the chip id.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

diff --cc Documentation/devicetree/bindings/serial/atmel-usart.txt
Simple merge

diff --cc arch/arm/boot/dts/at91rm9200.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9260.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9261.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9263.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9g45.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9n12.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9rl.dtsi
Simple merge

diff --cc arch/arm/boot/dts/at91sam9x5.dtsi
Simple merge

diff --cc arch/arm/boot/dts/sama5d3.dtsi
Simple merge

diff --cc arch/arm/boot/dts/sama5d4.dtsi
Simple merge