pinctrl: change result for unsupported API

Use the return value ENOSYS for unsupported API
- pinctrl_generic_set_state
- pinctrl_select_state

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/dm/pinctrl.h b/include/dm/pinctrl.h
index 695e78a..8b869c4 100644
--- a/include/dm/pinctrl.h
+++ b/include/dm/pinctrl.h
@@ -495,7 +495,7 @@
 static inline int pinctrl_generic_set_state(struct udevice *pctldev,
 					    struct udevice *config)
 {
-	return -EINVAL;
+	return -ENOSYS;
 }
 #endif
 
@@ -512,7 +512,7 @@
 static inline int pinctrl_select_state(struct udevice *dev,
 				       const char *statename)
 {
-	return -EINVAL;
+	return -ENOSYS;
 }
 #endif