rlc: Do not raise_v_q in receive_bsn

Currently gprs_rlc_ul_window::receive_bsn calls raise_v_q and returns
the number of RLC data blocks that can be taken from the queue. This
does not fit the EGPRS feature to put 2 independant data blocks in a
single RLC block.

This commit removes raise_v_q from receive_bsn, hence it must be
called explicitely to get the number of processable data blocks.

Sponsored-by: On-Waves ehf
diff --git a/src/rlc.cpp b/src/rlc.cpp
index 9f5c61d..bafc56e 100644
--- a/src/rlc.cpp
+++ b/src/rlc.cpp
@@ -220,10 +220,9 @@
 	return count;
 }
 
-uint16_t gprs_rlc_ul_window::receive_bsn(const uint16_t bsn)
+void gprs_rlc_ul_window::receive_bsn(const uint16_t bsn)
 {
 	m_v_n.mark_received(bsn);
 	raise_v_r(bsn);
 
-	return raise_v_q();
 }