Only enabled if PIN_LED_TXL or PIN_LED_RXL is defined

Resolve compiler warning from performing arithmetic on void pointers

The shortcut has some issues:

- sometimes it fails when sending an odd number of bytes (may be
  due to memory alignment?)
- the data pointer should point to "stable" data (and this is not
  guaranteed by caller, it may be some sort of temporary buffer)
- the SRAM is not guaranteed to start at 0x20000000

All the above problems must be properly fixed before reenabling
this part

* fix in_endpoint buffer size (was too big)
* use the same EP for CDC_ENDPOINT_OUT and CDC_ENDPOINT_IN (different buffers)
* fix CDC_ENDPOINT_IN ep type

It seems that

   #include <stdint.h>

is able to undef "min" and "max" previously defined. With this
commit we make sure that they are defined as last.

Fix #10

This reverts commit bc7115b104428f9bea4fdfa1b6af245085f6f542.

Signed-off-by: Jean-Christophe BUDA <jean-christophe.buda@atmel.com>