added parallelization of fep and encoding

cmake_targets/build_oai

openair1/PHY/LTE_TRANSPORT/dlsch_coding.c

openair1/PHY/LTE_TRANSPORT/proto.h

openair1/PHY/defs.h

openair1/SCHED/phy_procedures_lte_eNb.c

targets/ARCH/COMMON/common_lib.c

targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp

targets/RT/USER/lte-enb.c

targets/RT/USER/lte-ru.c

targets/RT/USER/lte-softmodem.c

targets/RT/USER/lte-softmodem.h