The remaining_bits_len is correctly decremented while encoding
CSN_RECURSIVE_ARRAY for fixing the bug.
Details of the bug is in https://projects.osmocom.org/issues/1641
During introduction of basic EGPRS feature new hex dump message
PUASS, from a different working network log was used in Unit test.
It exposed the issue of incorrect handling of recursive array
encoding in osmo-pcu.
Fixes: OS#1641