Modify the file names and deifinitions relater to Marvell
db-77f3720 board support. Convert these names to more generic
armada-37xx platform for future addition of more boards
based on the same SoC family.

Signed-off-by: Konstantin Porotchkin
Cc: Stefan Roese
Cc: Igal Liberman
Cc: Nadav Haklai
Signed-off-by: Stefan Roese