Changes

cbsp_link.c: Update somo_stream read_cb2 functions to accommodate for new API param

libosmo-netif (not yet released) stream_{cli,srv} osmo_io read_cb API was
updated to provide read result status. Hence, now API users
can account for lower layer errors and act properly, like it used to
do with the previous ofd backend.

This commit partially reverts some error code paths removed in
85687bf176e4b9663f2396a27c28b49221c72fa3 when converting code to use
osmo_io osmo_stream backend.

Change-Id: I4cce5cb6ca98bc28a67dd6e927e9cdfd2312851a
Depends: libosmo-netif.git Change-Id I395c75ff1e9904757ce1d767a9ac2f779593c4c8