sunxi: Move cpu independent code to mach directory

Some of the code in arch/arm/cpu/armv7/sunxi is actually armv7 specific, while
most of it is just generic code that could as well be used on an AArch64 SoC.

Move all files that are not really tied to armv7 into a new mach-sunxi
directory.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>