dtc: Fix memory leak in character literal parsing

The data struct used for parsing character literals was never freed
resulting in a few bytes leaked for every character.

Signed-off-by: Gabriel Smith <ga29smith@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/dtc-lexer.l b/dtc-lexer.l
index 40bbc87..c600603 100644
--- a/dtc-lexer.l
+++ b/dtc-lexer.l
@@ -189,16 +189,16 @@
 			if (d.len == 1) {
 				lexical_error("Empty character literal");
 				yylval.integer = 0;
-				return DT_CHAR_LITERAL;
+			} else {
+				yylval.integer = (unsigned char)d.val[0];
+
+				if (d.len > 2)
+					lexical_error("Character literal has %d"
+						      " characters instead of 1",
+						      d.len - 1);
 			}
 
-			yylval.integer = (unsigned char)d.val[0];
-
-			if (d.len > 2)
-				lexical_error("Character literal has %d"
-					      " characters instead of 1",
-					      d.len - 1);
-
+			data_free(d);
 			return DT_CHAR_LITERAL;
 		}