pinctrl: qcom: Handle get_function_mux failure

Presently, get_function_mux returns an unsigned int and cannot
differentiate between failure and correct function value. Change its
return type to int and check for failure in the caller.

Additionally, updated drivers/pinctrl/qcom/pinctrl-*.c to accommodate the
above return type change. Only compile test done.

Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
Link: https://lore.kernel.org/r/20250226064505.1178054-5-quic_varada@quicinc.com
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/drivers/pinctrl/qcom/pinctrl-qcom.c b/drivers/pinctrl/qcom/pinctrl-qcom.c
index 26a3fba..24d0319 100644
--- a/drivers/pinctrl/qcom/pinctrl-qcom.c
+++ b/drivers/pinctrl/qcom/pinctrl-qcom.c
@@ -92,7 +92,10 @@
 			  unsigned int func_selector)
 {
 	struct msm_pinctrl_priv *priv = dev_get_priv(dev);
-	u32 func = priv->data->get_function_mux(pin_selector, func_selector);
+	int func = priv->data->get_function_mux(pin_selector, func_selector);
+
+	if (func < 0)
+		return func;
 
 	/* Always NOP for special pins, assume they're in the correct state */
 	if (qcom_is_special_pin(&priv->data->pin_data, pin_selector))