osmo-bts-trx: amr_loop: log if AMR mode remains unchanged
osmo-bts-trx: amr_loop: log if AMR mode remains unchanged

Change-Id: I0272d11cfaad0e1c13d2858b3bc61d6527898018
Related: SYS#5917, OS#4984

osmocom/osmo-bts,osmocom/osmo-bts,osmocom/osmo-bts