Add merging of labelled subnodes. This patch allows the following

syntax:

/ {
	child {
		label: subchild {
		};
	};
};

&label {
	prop = "value";
};

which will result in the following tree:

/ {
	child {
		label: subchild {
			prop = "value";
		};
	};
};

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

dtc-lexer.l

@@ -109,7 +109,7 @@ static int pop_input_file(void);
 			return DT_LITERAL;
 		}
 
-\&{LABEL}	{	/* label reference */
+<*>\&{LABEL}	{	/* label reference */
 			DPRINT("Ref: %s\n", yytext+1);
 			yylval.labelref = xstrdup(yytext+1);
 			return DT_REF;