driver core: Add device_is_dependent() to linux/device.h

DT implementation of fw_devlink needs this function to detect cycles. So
make it available.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/base/core.c

@@ -121,7 +121,7 @@ int device_links_read_lock_held(void)
  * Check if @target depends on @dev or any device dependent on it (its child or
  * its consumer etc).  Return 1 if that is the case or 0 otherwise.
  */
-static int device_is_dependent(struct device *dev, void *target)
+int device_is_dependent(struct device *dev, void *target)
 {
 	struct device_link *link;
 	int ret;

include/linux/device.h

@@ -829,6 +829,7 @@ extern int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid);
 extern const char *device_get_devnode(struct device *dev,
 				      umode_t *mode, kuid_t *uid, kgid_t *gid,
 				      const char **tmp);
+extern int device_is_dependent(struct device *dev, void *target);
 
 static inline bool device_supports_offline(struct device *dev)
 {