Crypto: chelsio - Fixes a hang issue during driver registration

This issue occurs only when multiadapters are present. Hang
happens because assign_chcr_device returns u_ctx pointer of
adapter which is not yet initialized as for this adapter cxgb_up
is not been called yet.

The last_dev pointer is used to determine u_ctx pointer and it
is initialized two times in chcr_uld_add in chcr_dev_add respectively.

The fix here is don't initialize the last_dev pointer during
chcr_uld_add. Only assign to value to it when the adapter's
initialization is completed i.e in chcr_dev_add.

Fixes: fef4912b ("crypto: chelsio - Handle PCI shutdown event").

Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>