osmo-bts-trx: prettify Makefile.am: make it git friendly
osmo-bts-trx: prettify Makefile.am: make it git friendly

Change-Id: I0991910e0ffa6140f20c49bd2f0ad9b42cf231ba

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