xprtrdma: Re-organize the switch() in rpcrdma_conn_upcall

Clean up: Eliminate the FALLTHROUGH into the default arm to make the
switch easier to understand.

Also, as long as I'm here, do not display the memory address of the
target rpcrdma_ep. A hashed memory address is of marginal use here.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>