tbf/rlc: Move the v_n handling into a dedicated object
diff --git a/src/tbf.h b/src/tbf.h
index 9560e3c..4718707 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -171,7 +171,7 @@
 		} dl;
 		struct {
 			gprs_rlc_ul_window window;
-			char v_n[RLC_MAX_SNS/2]; /* receive state array */
+			gprs_rlc_v_n v_n;
 			int32_t rx_counter; /* count all received blocks */
 			uint8_t n3103;	/* N3103 counter */
 			uint8_t usf[8];	/* list USFs per PDCH (timeslot) */