VBUS drive is supported on AXP221 and later PMICs. Rework the macros
so we can support this on later PMICs without too much work.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>