osmo-bts-trx: amr_loop: simplify trx_loop_amr_set()
osmo-bts-trx: amr_loop: simplify trx_loop_amr_set()

Change-Id: Ibeed00ef48450edfe1e0d4e179fb4c777b11beb9
Related: SYS#5917, OS#4984

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