checkpatch: Remove reference to legacy IP stack

Old uIP based legacy IP stack is no longer there so it can
be removed from checkpatch conf file.

Change-Id: I2a17391f9cc8c0f8f8b81d520be1db8e2e8608f7
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
1 file changed