pinctrl: baytrail: add warning for BYT_VAL_REG retrieval failure

Add warning for BYT_VAL_REG retrieval failure and continue such case
to avoid unintended reads/writes in pm_ops.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20230616203356.27343-3-raag.jadav@intel.com


Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>