osmux: don't store conn ptr inside shared osmux_handle

The struct osmux_handle is a shared structure which goes together 1-1
with libosmo-netif's struct osmux_in_handle, which is common to all CIDs
to be muxed together. Hence, it makes no sense to store a specific conn
object to it, since it actually manages several of them. Hence, all the
conn specific stuff must be handled beforehand, not at osmux deliver
time.

Related: SYS#5987
Change-Id: Ie739b556e9eb7d3133e798831a09728c7cc87135
1 file changed