reset: use ENOTSUPP instead of ENOSYS

ENOSYS is reserved to report invalid syscalls to userspace.
Consistently return ENOTSUPP to indicate that the driver doesn't support
the functionality or the reset framework is not enabled at all.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/core.c

@@ -95,7 +95,7 @@ int reset_control_reset(struct reset_control *rstc)
 	if (rstc->rcdev->ops->reset)
 		return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
 
-	return -ENOSYS;
+	return -ENOTSUPP;
 }
 EXPORT_SYMBOL_GPL(reset_control_reset);
 
@@ -108,7 +108,7 @@ int reset_control_assert(struct reset_control *rstc)
 	if (rstc->rcdev->ops->assert)
 		return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
 
-	return -ENOSYS;
+	return -ENOTSUPP;
 }
 EXPORT_SYMBOL_GPL(reset_control_assert);
 
@@ -121,7 +121,7 @@ int reset_control_deassert(struct reset_control *rstc)
 	if (rstc->rcdev->ops->deassert)
 		return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
 
-	return -ENOSYS;
+	return -ENOTSUPP;
 }
 EXPORT_SYMBOL_GPL(reset_control_deassert);
 
@@ -136,7 +136,7 @@ int reset_control_status(struct reset_control *rstc)
 	if (rstc->rcdev->ops->status)
 		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
 
-	return -ENOSYS;
+	return -ENOTSUPP;
 }
 EXPORT_SYMBOL_GPL(reset_control_status);
 

include/linux/reset.h

@@ -74,7 +74,7 @@ static inline void reset_control_put(struct reset_control *rstc)
 
 static inline int device_reset_optional(struct device *dev)
 {
-	return -ENOSYS;
+	return -ENOTSUPP;
 }
 
 static inline struct reset_control *__must_check reset_control_get(
@@ -94,19 +94,19 @@ static inline struct reset_control *__must_check devm_reset_control_get(
 static inline struct reset_control *reset_control_get_optional(
 					struct device *dev, const char *id)
 {
-	return ERR_PTR(-ENOSYS);
+	return ERR_PTR(-ENOTSUPP);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional(
 					struct device *dev, const char *id)
 {
-	return ERR_PTR(-ENOSYS);
+	return ERR_PTR(-ENOTSUPP);
 }
 
 static inline struct reset_control *of_reset_control_get(
 				struct device_node *node, const char *id)
 {
-	return ERR_PTR(-ENOSYS);
+	return ERR_PTR(-ENOTSUPP);
 }
 
 static inline struct reset_control *of_reset_control_get_by_index(