libfdt: fdt_check_full: Handle FDT_NOP when FDT_END is expected

fdt_check_full() makes the assumption that a FDT_END tag is present
immediately after the FDT_END_NODE tag related to the root node.

This assumption is not correct. Indeed, FDT_NOP tags can be present
between this FDT_END_NODE tag and the FDT_END tag.

Handle those possible FDT_NOP tags.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Message-ID: <20260210173349.636766-8-herve.codina@bootlin.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

libfdt/fdt_check.c

@@ -43,7 +43,7 @@ int fdt_check_full(const void *fdt, size_t bufsize)
 			return nextoffset;
 
 		/* If we see two root nodes, something is wrong */
-		if (expect_end && tag != FDT_END)
+		if (expect_end && tag != FDT_END && tag != FDT_NOP)
 			return -FDT_ERR_BADSTRUCTURE;
 
 		switch (tag) {