Make the channel ops struct const since there really isn't anything
there that needs to change at runtime. The only exception is the L2CAP
shell which was playing with the recv callback, however that can be
fixed by introducing a simple bool variable.
With tests/bluetooth/shell this reduces RAM consumption by 112 bytes
while adding only 16 bytes to flash consumption.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
0e91493ab4