The future support for applying a addon on a base device-tree needs to
modify properties retrieved by their offset.

fdt_getprop_by_offset() already exists to get a preperty by its offset
but the property returned is read-only. A writable returned property is
needed.

Fill the lack and introduce fdt_getprop_by_offset_w(), the write enabled
variant of fdt_getprop_by_offset().

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
 libfdt/libfdt.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 37459a6..0c654b1 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h

@@ -858,6 +858,12 @@ static inline struct fdt_property *fdt_get_property_w(void *fdt, int nodeoffset,
 #ifndef SWIG /* This function is not useful in Python */
 const void *fdt_getprop_by_offset(const void *fdt, int offset,
 				  const char **namep, int *lenp);
+static inline void *fdt_getprop_by_offset_w(const void *fdt, int offset,
+					    const char **namep, int *lenp)
+{
+	return (void *)(uintptr_t)fdt_getprop_by_offset(fdt, offset, namep,
+							lenp);
+}
 #endif
 
 /**

-- 
2.52.0