arm: armada-xp: Move SoC sources to mach-mvebu

arm: armada-xp: Move SoC sources to mach-mvebu

Move arch/arm/cpu/armv7armada-xp/* -> arch/arm/mach-mvebu/*

Since this platform will be extended to support other Marvell SoC's as
well, lets rename it directly to mvebu.

This will be used by the upcoming Armada 38x suport (A38x).

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Kevin Smith <kevin.smith@elecsyscorp.com>
Tested-by: Dirk Eibach <dirk.eibach@gdsys.cc>