sunxi: Group cpu core related controls together

Instead of listing individual registers for controls to each processor
core, list them as an array of registers. This makes accessing controls
by core index easier.

Also rename "cpucfg_sun6i.h" (which was unused anyway) to the more generic
"cpucfg.h", and add packed attribute to struct sunxi_cpucfg.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>