ARM: shmobile: kzm9g dts: Sync with kzm9g-reference dts

Sync the two DTS for the KZM9G board. The target is the file
"sh73a0-kzm9g.dts" and it is made identical to the DT reference
case with the exception of the compatbile string. In the future
the DT reference file will go away.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
[geert: Update for recent changes to sh73a0-kzm9g-reference.dts]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>