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-sm8550.c b/drivers/pinctrl/qcom/pinctrl-sm8550.c
index 25b972a..f7fcad0 100644
--- a/drivers/pinctrl/qcom/pinctrl-sm8550.c
+++ b/drivers/pinctrl/qcom/pinctrl-sm8550.c
@@ -68,8 +68,8 @@
 	return pin_name;
 }
 
-static unsigned int sm8550_get_function_mux(__maybe_unused unsigned int pin,
-					    unsigned int selector)
+static int sm8550_get_function_mux(__maybe_unused unsigned int pin,
+				   unsigned int selector)
 {
 	return msm_pinctrl_functions[selector].val;
 }