gpio: dwapb: Remove unnecessary error message

In dwapb_get_reset(), if devm_reset_control_get_optional_shared() fails,
an error message is printed even if the failure is the benign
EPROBE_DEFER error due to the reset controller not yet being
initialized. Use dev_err_probe() to handle
devm_reset_control_get_optional_shared() errors to avoid unnecessarilly
printing an error message for the deferred probe error.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>