checkpatch: add ignore for net/ip/contiki directory

Added rule to ignore net/ip/contiki content in the checkpatch style.

Change-Id: I06d8575d2a00d0032099c8a6d804fef3aaad8381
Signed-off-by: Javier B Perez <javier.b.perez.hernandez@intel.com>
1 file changed