Allow multipart property values

At present each property definition in a dts file must give as the
value either a string ("abc..."), a bytestring ([12abcd...]) or a cell
list (<1 2 3 ...>).  This patch allows a property value to be given as
several of these, comma-separated.  The final property value is just
the components appended together.  So a property could have a list of
cells followed by a string, or a bytestring followed by some cells.
Cells are always aligned, so if cells are given following a string or
bytestring which is not a multiple of 4 bytes long, zero bytes are
inserted to align the following cells.

The primary motivation for this feature, however, is to allow defining
a property as a list of several strings.  This is what's needed for
defining OF 'compatible' properties, and is less ugly and fiddly than
using embedded \0s in the strings.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>

dtc-lexer.l

@@ -123,6 +123,15 @@ REFCHAR		({PROPCHAR}|{UNITCHAR}|[/@])
 			return ']';
 		}
 
+,		{ /* Technically this is a valid property name,
+		     but we'd rather use it as punctuation, so detect it
+		     here in preference */
+			yylloc.first_line = yylineno;
+			DPRINT("Char (propname like): %c (\\x%02x)\n", yytext[0],
+				(unsigned)yytext[0]);
+			return yytext[0];
+		}
+
 {PROPCHAR}+	{
 			yylloc.first_line = yylineno;
 			DPRINT("PropName: %s\n", yytext);