app/testpmd: remove duplicated Rx offload commands

app/testpmd: remove duplicated Rx offload commands

The testpmd application provides two sets of commands for RX offload
flags configuration. The purpose of this patch is to eliminate this
duplication by removing the old set of commands:
“port config all crc-strip|scatter|rx-cksum|rx-timestamp|hw-vlan|
hw-vlan-filter|hw-vlan-strip|hw-vlan-extend on|off”

The other commands set that can be used instead in order to enable
or disable the same RX offloading flags on all RX queues of a port is:
"port config <port_id> rx_offload crc_strip|scatter|ipv4_cksum|
udp_cksum|tcp_cksum|timestamp|vlan_strip|vlan_filter|vlan_extend on|off"

This patch also fixes the "drop-en" command, which enables packets
dropping on all RX queues of all ports when no receive buffers available
“port config all drop-en on|off”

Fixes: 384161e00627 ("app/testpmd: adjust on the fly VLAN configuration")
Cc: stable@dpdk.org
Signed-off-by: Flavia Musatescu <flavia.musatescu@intel.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>