FROMGIT: add fdt_path_getprop_namelen() helper

Add a wrapper for fdt_getprop_namelen() allowing one to specify the node
by path instead of offset.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

(cherry-picked from commit df093279282ca0cff4d20ceb3bb5857117ed4cc4 git://git.kernel.org/pub/scm/utils/dtc/dtc.git main)

Test: N/A
Change-Id: If9a102a622dfa726b7cb10f58c38f1b52d233be6
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index e61df25..31f78e2 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -525,6 +525,18 @@
 	return fdt32_ld_(php);
 }
 
+static const void *fdt_path_getprop_namelen(const void *fdt, const char *path,
+					    const char *propname, int propnamelen,
+					    int *lenp)
+{
+	int offset = fdt_path_offset(fdt, path);
+
+	if (offset < 0)
+		return NULL;
+
+	return fdt_getprop_namelen(fdt, offset, propname, propnamelen, lenp);
+}
+
 const char *fdt_get_alias_namelen(const void *fdt,
 				  const char *name, int namelen)
 {