netdevsim: add ipsec hw_features

Currently, netdevsim only sets dev->features, which makes the ESP features
fixed. For example:

# ethtool -k eni0np1 | grep esp
tx-esp-segmentation: on [fixed]
esp-hw-offload: on [fixed]
esp-tx-csum-hw-offload: on [fixed]

This patch adds the ESP features to hw_features, allowing them to be
changed manually. For example:

# ethtool -k eni0np1 | grep esp
tx-esp-segmentation: on
esp-hw-offload: on
esp-tx-csum-hw-offload: on

Suggested-by: Sabrina Dubroca <[e-mail]>
Signed-off-by: Hangbin Liu <[e-mail]>
Reviewed-by: Sabrina Dubroca <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/netdevsim/ipsec.c

···
 				 NETIF_F_GSO_ESP)
 
 	ns->netdev->features |= NSIM_ESP_FEATURES;
+	ns->netdev->hw_features |= NSIM_ESP_FEATURES;
 	ns->netdev->hw_enc_features |= NSIM_ESP_FEATURES;
 
 	ns->ipsec.pfile = debugfs_create_file("ipsec", 0400,