dts/imx: rename uart labels to consistent with hw spec

UART1/UART2/... is more readable than UART0/UART1/... .
Remove redundant UART comments.

Signed-off-by: Richard Zhao <richard.zhao@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

diff --cc arch/arm/boot/dts/imx51-babbage.dts
Simple merge

diff --cc arch/arm/boot/dts/imx51.dtsi
Simple merge

diff --cc arch/arm/boot/dts/imx53-ard.dts
Simple merge

diff --cc arch/arm/boot/dts/imx53-evk.dts
Simple merge

diff --cc arch/arm/boot/dts/imx53-qsb.dts
Simple merge

diff --cc arch/arm/boot/dts/imx53-smd.dts
Simple merge

diff --cc arch/arm/boot/dts/imx53.dtsi
Simple merge

diff --cc arch/arm/boot/dts/imx6q-sabreauto.dts
Simple merge

diff --cc arch/arm/boot/dts/imx6q.dtsi
Simple merge