ARM: dts: aspeed: Fix I2C bus warnings

ARM: dts: aspeed: Fix I2C bus warnings

dtc has new checks for I2C buses. The ASpeed dts files have a node named
'i2c' which causes a false positive warning. As the node is a 'simple-bus',
correct the node name to be 'bus' to fix the warnings.

arch/arm/boot/dts/aspeed-bmc-opp-lanyang.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-opp-romulus.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-ast2500-evb.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-arm-centriq2400-rep.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-intel-s2600wf.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-opp-witherspoon.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-opp-zaius.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-portwell-neptune.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus
arch/arm/boot/dts/aspeed-bmc-quanta-q71l.dtb: Warning (i2c_bus_bridge): /ahb/apb/i2c@1e78a000: incorrect #size-cells for I2C bus

Cc: Joel Stanley <joel@jms.id.au>
Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: linux-aspeed@lists.ozlabs.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>