Update wfa_tg.c
Update wfa_tg.c

mySockfd value is asocket descriptor. the manual for the BSD socket() function states that an error is indicated by a negative value, usually -1.
A zero value is also a valid socket descriptor.
WFA-AlanTsai/Wi-FiTestSuite-Linux-DUT,WFA-DakeZhao/Wi-FiTestSuite-Linux-DUT,WFA-DakeZhao/Wi-FiTestSuite-Linux-DUT,WFA-AlanTsai/Wi-FiTestSuite-Linux-DUT,Wi-FiTestSuite/Wi-FiTestSuite-Linux-DUT,WFA-AlanTsai/Wi-FiTestSuite-Linux-DUT,WFA-HarshMadhiwalla/Wi-FiTestSuite-Linux-DUT,WFA-HarshMadhiwalla/Wi-FiTestSuite-Linux-DUT,WFA-DakeZhao/Wi-FiTestSuite-Linux-DUT,Wi-FiTestSuite/Wi-FiTestSuite-Linux-DUT