sunxi: Use CONFIG_MACH_SUN?I from Kconfig instead of CONFIG_SUN?I

Mostly automatic with:
    sed -i -e 's/CONFIG_\(SUN[45678]I\)/CONFIG_MACH_\1/g' $(git grep -l CONFIG_SUN[45678]I)
followed by removing the relevant #defines from include/configs/sun?i.h by
hand.

Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>