In openbsc.git Change-Id I61c18a7f021fcb1ec00d34a745f4e3ab03416c2d
we changed the gsm_bts_alloc() function signature to include
a second argument (the BTS number). This broke omso-bts, and this
commit is intended to make it build again.
Change-Id: I7ef7654d48c1cfc7e4ecb0b771553ec0740ce2bf