move statistics counter rlc_sent() to gprs_rlcmac_sched

The counter rlc_sent has nothing to do with the TBF.
The RLC packet got sent in the gprs_rlcmac_sched().

Change-Id: I5d2b910ea7cc250f17530406eda3be9b29b051fd
Reviewed-on: https://gerrit.osmocom.org/84
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
2 files changed