tools/mpy-tool.py: Fix offset of line number info. (#2)

Signed-off-by: Martin Milata <martin@martinmilata.cz>

(cherry picked from commit 359ca43)

tools/mpy-tool.py

@@ -229,6 +229,7 @@ def __init__(self, code_kind, bytecode, prelude_offset, qstrs, objs, raw_codes):
             self.ip, self.ip2, self.prelude = extract_prelude(self.bytecode, self.prelude_offset)
             self.simple_name = self._unpack_qstr(self.ip2)
             self.source_file = self._unpack_qstr(self.ip2 + 2)
+            self.line_info_offset = self.ip2 + 4
 
     def _unpack_qstr(self, ip):
         qst = self.bytecode[ip] | self.bytecode[ip + 1] << 8
@@ -361,7 +362,10 @@ def freeze_module(self, qstr_links=(), type_sig=0):
             print('        .n_def_pos_args = %u,' % self.prelude[5])
             print('        .qstr_block_name = %s,' % self.simple_name.qstr_id)
             print('        .qstr_source_file = %s,' % self.source_file.qstr_id)
-            print('        .line_info = fun_data_%s + %u,' % (self.escaped_name, 0)) # TODO
+            print(
+                '        .line_info = fun_data_%s + %u,'
+                % (self.escaped_name, self.line_info_offset)
+            )
             print('        .opcodes = fun_data_%s + %u,' % (self.escaped_name, self.ip))
             print('    },')
             print('    .line_of_definition = %u,' % 0) # TODO