ARM: dts: imx: use generic name bus

Per devicetree specification, generic names
are recommended to be used, such as bus.

i.MX AIPS is a AHB - IP bridge bus, so
we could use bus as node name.

Script:
sed -i "s/\<aips@/bus@/" arch/arm/boot/dts/imx*.dtsi
sed -i "s/\<aips@/bus@/" arch/arm/boot/dts/vf*.dtsi
sed -i "s/\<aips-bus@/bus@/" arch/arm/boot/dts/imx*.dtsi
sed -i "s/\<aips-bus@/bus@/" arch/arm/boot/dts/vf*.dtsi

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>