When application wants to send zero length data, packet is dropped.
And uip_appdatalen is wrongly assigned with total IP packet length.
Jira: ZEP-575
Change-Id: I7f714cbef74dc28b83db7a776ef80a3026ae120e
Signed-off-by: Ravi kumar Veeramally <ravikumar.veeramally@linux.intel.com>