arm64: mvebu: Rename db-88f7040 files to armada-8k

arm64: mvebu: Rename db-88f7040 files to armada-8k

This moves some of the Armada DB-88F7040 board specific files to a more
generic name: armada-8k. This is in preparation for the Armada-8k
support which will be added soon. And since both platforms share
most devices, lets also share most source files to not duplicate
the code here.

Signed-off-by: Stefan Roese <[email protected]>
Cc: Nadav Haklai <[email protected]>
Cc: Neta Zur Hershkovits <[email protected]>
Cc: Kostya Porotchkin <[email protected]>
Cc: Omri Itach <[email protected]>
Cc: Igal Liberman <[email protected]>
Cc: Haim Boot <[email protected]>
Cc: Hanna Hawa <[email protected]>