app/testpmd: remove duplicated offload display

app/testpmd: remove duplicated offload display

"show port cap all|<port_id>" was to display offload configuration of
port(s).

But later two other commands added to show same information in more
accurate way:
 show port (port_id) rx_offload configuration
 show port (port_id) tx_offload configuration

These new commands can both show port and queue level configuration,
also with their capabilities counterparts easier to see offload
capability and configuration of the port in similar syntax.

So the functionality is duplicated and removing this version, to favor
the new commands.

Another problem with this command is it requires each new offload to be
added into the function to display them, and there were missing offloads
that are not displayed, this requirement for sure will create gaps by
time as new offloads added.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Lance Richardson <lance.richardson@broadcom.com>
Acked-by: Xiaoyun Li <xiaoyun.li@intel.com>