encoding/rlc_copy_from_aligned_buffer: export written payload bytes via an argument

Require to count statistics for rlc_dl_payload_bytes.

Change-Id: I0e622acb1f13f7489946baf049de4ba1cde6a1fc
Reviewed-on: https://gerrit.osmocom.org/142
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
diff --git a/src/encoding.h b/src/encoding.h
index 94e9a02..710de78 100644
--- a/src/encoding.h
+++ b/src/encoding.h
@@ -91,6 +91,5 @@
 	static AppendResult rlc_data_to_dl_append(
 		struct gprs_rlc_data_block_info *rdbi, GprsCodingScheme cs,
 		gprs_llc *llc, int *offset, int *num_chunks,
-		uint8_t *data,
-		bool is_final);
+		uint8_t *data, bool is_final, int *count_payload);
 };