Use yylloc instead of yyloc

yylloc is the correct way to get token positioning information.
yyloc is a bison internal variable that only works by accident.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

dtc-parser.y

@@ -175,7 +175,7 @@ propdata:
 
 			if ($6 != 0)
 				if (fseek(file->file, $6, SEEK_SET) != 0)
-					srcpos_error(&yyloc,
+					srcpos_error(&yylloc,
 						     "Couldn't seek to offset %llu in \"%s\": %s",
 						     (unsigned long long)$6,
 						     $4.val,