crimson/net: do not print non-void* pointer

crimson/net: do not print non-void* pointer

to address the failure like

fmt/core.h:902:19: error: static assertion failed: formatting of non-void pointers is disallowed
  902 |     static_assert(!sizeof(T), "formatting of non-void pointers is disallowed");
      |                   ^~~~~~~~~~

and i searched around, couldn't find any other
statement printing the address of message, so
i think it's not of much use to print their
addresses in a single place, unless we can cross
check them in different places.

Signed-off-by: Kefu Chai <kchai@redhat.com>