BTS_Tests: print DL TCH length in f_TC_speech_osmux()

I forgot to update this function in [1].

Change-Id: I2a2dccd32aaf94afc31bd44f14fdc1cfdf554d2d
Related: [1] I5848bd8acd220c1c4d2db01b71bb57e785dc9de7
1 file changed