sunxi-rtc: Add sun7i support

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: unify gpio.h

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sun7i: Document why we don't use the scu

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sun7i: Remove super-standby support fixup

Removing the dram parameter parsing was not a good idea, since for sun7i that
is used for regular standby too.

Also do some misc. cleanups.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Merge remote-tracking branch 'jwrdegoede/sunxi-3.4-a20-wip' into sunxi-3.4-a20