mmc: pwrseq_simple: fix error path in mmc_pwrseq_simple_alloc

mmc: pwrseq_simple: fix error path in mmc_pwrseq_simple_alloc

The current error-path code (when gpiod_get_index() reports
an error) can never free pwrseq->reset_gpios[0], but might
try to tree pwrseq->reset_gpios[-1], which has unfortunate
consequences.

Signed-off-by: NeilBrown <neil@brown.name>
Fixes: 934f1f48330ed695927a51fa068dc5d673f2da19
Acked-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reported-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>