ARM: shmobile: kzm9g-reference dts: Sort i2c0 children by unit address

While at it rename the ak4648 node to "codec" to describe the device's
function instead of its model, and move its device-specific property
after its generic properties.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>