cxgb4/chcr : Register to tls add and del callback

A new macro is defined to enable ktls tx offload support on Chelsio
T6 adapter. And if this macro is enabled, cxgb4 will send mailbox to
enable or disable ktls settings on HW.
In chcr, enabled tx offload flag in netdev and registered tls_dev_add
and tls_dev_del.

v1->v2:
- mark tcb state to close in tls_dev_del.
- u_ctx is now picked from adapter structure.
- clear atid in case of failure.
- corrected ULP_CRYPTO_KTLS_INLINE value.

v2->v3:
- add empty line after variable declaration.
- local variable declaration in reverse christmas tree ordering.

Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>