One check introduced by previous commit was not necessary.

768*8 is too small, in 20MHz, the phy-test mode
(in default mode?) has a buffer of size 6378.

Let's set the buffer size to the input's one plus 4 bytes
(to accomodate for CRC, not sure about this).

We use the odd/even dlsch corresponding to the configured
subframe. It may not be the right thing to do.

  for all processing including oaisim

Conflicts:
	openair1/PHY/LTE_TRANSPORT/dlsch_llr_computation.c

 in dlsim_tm4 to distinguish from the old runs.

mcs1 was taken instead of mcs2 in several places.

Before that the scaling was aplied in precoder.
Now it is done in sqrt_rho_a and sqrt_rho_b.
For TM4 there still remains 1/sqrt(2) instead of
1/2 both at the transmitter and receievr side.

Prior to this commit, the following command failed to build dlsim:
    ./build_oai --phy_simulators -c

Choice has been made to define it in a .h file as a static inline
function.

The compilation line was:
    ./build_oai --eNB -w USRP

The file openairinterface5g/cmake_targets/log/lte-softmodem.Rel10.txt
has been checked and all LOG_X (and 'msg') warnings have been fixed.