This patch fixes a bug introduced in the v3.10 merge window.

The AB8500 External Regulator driver has recently landed upstream,
which registers each of the 3 external regulators located on the
AB8500. If these regulators are marked as 'always on', there is a
potential for power-loss. If they're not and are seemingly unused
the Regulator subsystem will attempt to disable them to save power.
This causes an issue for AUX1, AUX2 and AUX3 as they obtain their
power from EXT3. So we're specifying that here to prevent EXT3 from
being powered down.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>