sunxi: Convert CONFIG_SATAPWR to Kconfig

Convert the CONFIG_SATAPWR into kconfig.
Thanks to that, many SYS_EXTRA_OPTIONS can be removed from some
defconfigs.

Signed-off-by: Mylène Josserand <mylene.josserand@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>