Firstly, do not store the encoded AMR length-value bits in gsm_lchan->*
before an activation/modify has actually succeeded.
And secondly, do not store the AMR LV structure in struct gsm_lchan at
all, but only generate the TLV exactly when a message is being composed.
In gsm48_multirate_config(), generate the LV directly to a msgb instead
of a static buffer first. gsm0408_test.c expected output verifies that
the generated LV bytes remain unchanged.
In lchan_mr_config(), introduce a target mr_conf argument, so that Chan
Act and Mode Modify may generate the filtered AMR config to different
locations (lchan->{activate,modify}.mr_conf_filtered).
Only after receiving an ACK for Activate/Modify, set
lchan->current_mr_conf from lchan->{activate,modify}.mr_conf_filtered.
Use the properly scoped lchan->activate.mr_conf_filtered for Chan Act,
lchan->modify.mr_conf_filtered for Mode Modify and
new_lchan->current_mr_conf for Handover Command as appropriate.
Related: SYS#5315 OS#4940 OS#3787 OS#3833
Change-Id: Ie57f9d0e3912632903d9740291225bfd1634ed47
d508143dd3