From: Dong Aisheng <redacted>

Currently most code to get child number in kernel are almost same,
add a helper to implement this function for dt to use.

Signed-off-by: Dong Aisheng <redacted>
Cc: Grant Likely <redacted>
Cc: Rob Herring <redacted>
---
 include/linux/of.h |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/include/linux/of.h b/include/linux/of.h
index 4948552..09d53dc 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h

@@ -189,6 +189,18 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
 	for (child = of_get_next_child(parent, NULL); child != NULL; \
 	     child = of_get_next_child(parent, child))
 
+static inline int of_get_child_number(struct device_node *np)