regulator: fixed: Remove workaround to handle of_get_named_gpio() return

The GPIO interface of_get_named_gpio() has implemented the proper
error returns even EPROBE_DEFER and hence caller need not to
implement any workaround for translating the returned error.

Remove the workaround implemented to handle the return of
of_get_named_gpio().

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>