regulator: s2mps11: Don't zero allocated memory for external control

The driver was allocating memory for storing GPIOs for external control
with unnecessary GFP_ZERO flag. Then right after allocation it
initialized memory to -EINVAL in loop. Skip the GFP_ZERO flag.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>