hwspinlock: add a check of devm_regmap_field_alloc in qcom_hwspinlock_probe

devm_regmap_field_alloc may fails, priv field might be error pointer and
cause illegal address access later.

Signed-off-by: Kang Chen <void0red@gmail.com>
Link: https://lore.kernel.org/r/20230227004116.1273988-1-void0red@gmail.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>