scheduler_trx.c: Fix typos, improve comments, cosmetics
scheduler_trx.c: Fix typos, improve comments, cosmetics

Change-Id: I5e2ce70aea8d62657ce3a7d6c16e5a7f8b76c22f

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