Received UDP packet was counted twice in statistics, first in udp_input and then again in udp_found.
Fix this to use same logic as in uip.c: valid packet is counted only in udp_found.
Merge pull request #452 from AriZuu/uip6-udp-stats-twice-fix

Received UDP packet was counted twice in statistics, first in udp_input ...
Added a way to obtain the RSSI from the CC2538 RF core
Added a function for setting promiscous mode on the CC2538 RF core
Added header declarations for cc2538_rf_read_rssi() and cc2538_rf_set_promiscous_mode()
Added missing argument declaration
Merge pull request #458 from adamdunkels/push/cc2538-rf

CC2538 RF core additions