vty: fix documentation for 'rx-sps (1|4)' and 'tx-sps (1|4)'
vty: fix documentation for 'rx-sps (1|4)' and 'tx-sps (1|4)'

Change-Id: I70d9b16fd2b1c2cbaafc978724369cd2c9679cbd

osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx,osmocom/osmo-trx