sama5d3xek: Modifty sama5d3xmb.dtsi to adapt to rev.D MB

In the meantime rename the old sama5d3xmb.dtsi to sama5d3xmb_revc.dtsi.

The difference between revC and revD MB is the wm8904 is moved
from TWI0 to TWI1.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
sama5d3xek: add revC MB dts file for all sama5d3xek board

The only difference is revc dts inlcudes sama5d3xmb_revc.dtsi instead.
Now we use _revC variants for all mother board revision C and below.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
sama5d3xek: enable both ISI and sound for sama5d3xek board

In latest rev.D MB, it support both ISI and sound.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
sama5d3xek: rename sama5d3xmb_isi.dtsi to sama5d3xmb_revc_isi.dtsi

Only rev.C dts file need ISI or sound selection. So rename it.

Signed-off-by: Josh Wu <josh.wu@atmel.com>