generator: _c_accessor_get_length: remove buggy special case

generator: _c_accessor_get_length: remove buggy special case

The function _c_accessor_get_length had a special case handling
for intermixed var and fixed size fields.

However:
* The implementation of that special case was buggy:
  It tried to call a python-dict as a function which causes
  Python to abort the program with a stacktrace and error message.
  So this code was never used.

* The case it tried to handle is handeled elsewhere in the
  meantime: in _c_helper_absolute_name by previous patches
  made by me.

Message-ID: <1409845851-38950-3-git-send-email-chris@demorecorder.com>
Patch-Thread-Subject: [Xcb] support popcount of a list and associated xml changes
Patch-Set: PopcountList
Patch-Number: libxcb 3/4
Patch-Version: V1
Signed-off-by: Christian Linhart <chris@DemoRecorder.com>