This creates a `struct net_conn_handle` that's only used as an opaque
pointer. The purpose is to avoid assigning a void* to a void** in
connection registering/unregistering functions, avoiding a
previously-caught bug by issuing an incompatible pointer types warning:
warning: passing argument 7 of 'net_tcp_register' from
incompatible pointer type [-Wincompatible-pointer-types]
Suggested by Andy Ross in 5beec6. This particular commit didn't catch
any bugs, but the one caught in 5beec6 wouldn't exist if this were in
place at the time.
Change-Id: I5c13fb4c5826adce6397feb7b400d36e426c4a87
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
ad1a9d088d