regulator: gpio-regulator: Fix logical error in for() loop

The cond-statement of this particular for() loop will always be
true as long as at least one voltage-shifting GPIO is present.
If it wasn't for the break below, we'd be stuck in a forever loop.
This patch inserts the correct cond-statement into the statement.

Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>